#!r6rs, #!r7rs or
#!compatible. For more details, see
Predefined reader macros.
-r6 option to run the script strict R6RS mode.
Multiple import of the same identifier is allowed. The value which
imported at the last will be used.sagittarius
on Unix like environment and sash on Windows environment.
-r option with Scheme standard number, currently 6
and 7 are supported, forces to run Sagittarius on strict standard
mode. For example, entire script is read then evaluated on R6RS
(-r6 option) mode. Thus macros can be located below the main script.
Detail options are given with option "-h".sash is also provided
on Unix like environment. However this may not exist if Sagittarius is built
with disabling symbolic link option.
sagittarius, it bounds an internal
variable to list of the remaining command-line arguments which you can get with
the command-line procedure, then loads the Scheme program. If the first
line of scheme-file begins with "#!", then Sagittarius ignores the
entire line. This is useful to write a Scheme program that works as an
executable script in unix-like systems.
Typical Sagittarius script has the first line like this:
#!/usr/local/bin/sagittariusor
#!/bin/env sagittariusThe second form uses "shell trampoline" technique so that the script works as far as
sagittarius is in the PATH.
After the script file is successfully loaded, then Sagittarius will process all
toplevel expression the same as Perl.
Now I show a simple example below. This script works like cat(1), without
any command-line option processing and error handling.
#!/usr/local/bin/sagittarius
(import (rnrs))
(let ((args (command-line)))
(unless (null? (cdr args))
(for-each (lambda (file)
(call-with-input-file file
(lambda (in)
(display (get-string-all in)))))
(cdr args)))
0)
If the script file contains main procedure, then Sagittarius execute
it as well with one argument which contains all command line arguments. This
feature is defined in
SRFI-22. So the
above example can also be written like the following:
#!/usr/local/bin/sagittarius
(import (rnrs))
(define (main args)
(unless (null? (cdr args))
(for-each (lambda (file)
(call-with-input-file file
(lambda (in)
(display (get-string-all in)))))
(cdr args)))
0)
NOTE: the main procedure is called after all toplevel expressions
are executed.
sagittarius does not get any script file to process, then it will
go in to REPL (read-eval-print-loop). For developers' convenience, REPL
imports some libraries by default such as (rnrs).
If .sashrc file is located in the directory indicated HOME or
USERPROFILE environment variable, then REPL reads it before evaluating
user input. So developer can pre-load some more libraries, instead of typing
each time.
NOTE: .sashrc is only for REPL, it is developers duty to load all
libraries on script file.
library
syntax please see the R6RS document described in bellow sections.
(library (foo) (export bar) (import (rnrs)) (define bar 'bar) )The library named
(foo) must be saved the file
named foo.scm, foo.ss, foo.sls or foo.sld (I use
.scm for all examples) and located on the loading path, the value is
returned by calling add-load-path with 0 length string.
If you want to write portable code yet want to use Sagittarius specific
functionality, then you can write implementation specific code separately using
.sagittarius.scm, .sagittarius.ss, .sagittarius.sls or
.sagittarius.sld extensions. This functionality is implemented almost
all R6RS implementation. If you use R7RS style library syntax, then you can
also use cond-expand to separate implementation specific
functionalities.
If you don't want to share a library but only used in specific one, you can
write both in one file and name the file you want to show. For example;
(library (not showing) ;; exports all internal use procedures (export ...) (import (rnrs)) ;; write procedures ... ) (library (shared) (export shared-procedure ...) (import (rnrs) (not showing)) ;; write shared procedures here )Above script must be saved the file named
shared.scm. The order of
libraries are important. Top most dependency must be the first and next is
second most, so on.
Note: This style can hide some private procedures however if you want to write
portable code, some implementations do not allow you to write this style.
SAGITTARIUS_CACHE_DIR
HOME
SAGITTARIUS_CACHE_DIR
TEMP
TMP
SAGITTARIUS_CACHE_DIR is found then it will be used.
The caching compiled file is carefully designed however the cache file might be
stored in broken state. In that case use -c option with
sagittarius, then it will wipe all cache files. If you don't want to use
it, pass -d option then Sagittarius won't use it.
(import (the-library-1)
(the-library-2))
When this script is run, then the libraries will be cached in the cache
directory.
Note: The cache files are stored with the names converted from original library
files' absolute path. So it is important that users' libraries are already
installed before precompiling, otherwise Sagittarius won't use the precompiled
cache files.
#t instead of #f with -r6
command line option or doing it on a library:
(import (rnrs) (for (rnrs eval) expand))
(define-syntax foo
(lambda(ctx)
(syntax-case ctx ()
((_ id)
(free-identifier=?
#'id
(eval '(datum->syntax #'k 'bar) (environment '(rnrs))))))))
(define bar)
(display (foo bar))
This is because, Sagittarius doesn't have separated phases of macro expansion
and compilation. When foo is expanded, then the bar is not defined
yet or at least it's not visible during the macro expansion. So, both bars
are not bound, then free-identifier=? will consider them the same
identifiers.
"user". Here I list up all R6RS libraries. Some libraries contain
the same procedure ie. assoc which is in (rnrs (6)) and
(srfi :1 lists). In this case I will put a pointer to other library's
section.
If library specifies its version, Sagittarius, however, ignores it. This
behaviour may change in future.
import clauses of all other libraries. It must have the following form:
(identifier1 identifier2 ... version)where version is empty or has the following form:
(sub-version ...)
An export-clause names a set of imported and locally defined bindings to
be exported. It must have following form:
(export export-spec ...)export-spec must have one of the following forms:
identifier
(rename (identifier1 identifier2) ...)
rename spec
exports the binding named by identifier1 in each
(identifier1 identifier2) pairing, using identifier2 as
the external name.
import-clause specifies a set of bindings to be imported into the
library. It must have the following form:
(import import-spec ...)Each import-spec specifies a set of bindings to be imported into the library. An import-spec must be one of the following:
(for import-set import-level ...)
run
expand
(meta level)
(library reference)
(only import-set identifier ...)
(except import-set identifier ...)
(prefix import-set identifier)
(rename import-set (identifier1 identifier2) ...)
(identifier1 identifier2 ...)
(identifier1 identifier2 ... version)
for, library, only, except, prefix or rename is permitted only
within a library import-set. The import-set
(library reference) is otherwise equivalent to reference.
By default, all of an imported library's exported bindings are made visible
within an importing library using the names given to the bindings by the
imported library. The precise set of bindings to be imported and the names of
those bindings can be adjusted with the only, except, prefix and
rename forms described below.
only form produces a subset of the bindings from another
import-set, including only the listed identifiers. The included
identifiers should be in the original import-set.
except form produces a subset of the bindings from another
import-set, including all but the listed identifiers. All of the
excluded identifiers should be in the original import-set.
prefix form adds the identifier prefix to each name from
another import-set.
rename form (rename identifier1 identifier2 ...),
removes the bindings for identifier1 ... to form an intermediate
import-set, then adds the bindings back for the corresponding
identifier2 ... to form the final import-set. Each
identifier1 should be the original import-set, each
identifier2 should not be int the intermediate import-set, and
the identifier2's must be distinct.
(library (foo) (export bar) (import (rename (rnrs) (define def) (not-exist define) (define def))) (def bar) )
(rnrs (6)) is required by R6RS. It just export
all symbols from the libraries which are listed below.define form is a definition used to create variable
bindings and may appear anywhere other definitions may appear.
The first from of define binds variable to a new location before
assigning the value of expression to it.
(define add3 (lambda (x) (+ x 3)))
(add3 3)=> 6
(define first car)
(first '(1 2))=> 1
define is equivalent to
(define variable unspecified)where unspecified is a side-effect-free expression returning an unspecified value. In the third form of
define, formals must be either a sequence of
zero or more variables, or a sequence of one or more variables followed by a dot
. and another variable. This form is equivalent to
(define variable (lambda (formals) body ...))In the fourth form of
define, formal must be a single variable.
This form is equivalent to
(define variable (lambda formal body ...))
define-syntax form is a definition used to create keyword
bindings and may appear anywhere other definitions may appear.
Binds keyword to the value of expression, which must evaluate,
at macro-expansion time, to a transformer.
quote evaluates to the datum value represented by datum.
(quote a)=> a
(quote #(a b c))=> #(a b c)
(quote (+ 1 2))=> (+ 1 2)
lambda expression evaluates to a procedure. The
environment in effect when the lambda expression is evaluated is remembered as
part of the procedure. When the procedure is later called with some arguments,
the environment in which the lambda expression was evaluated is extended
by binding the variables in the parameter list to fresh locations, and the
resulting argument values are stored in those locations. Then, the expressions
in the body of the lambda expression are evaluated sequentially in
the extended environment. The results of the last expression in the body are
returned as the results of the procedure call.
(lambda (x) (+ x x))=> a procedure
((lambda (x) (+ x x)) 4)=> 8
=> 11((lambda (x) (define (p y) (+ y 1)) (+ (p x) x)) 5)
(define reverse-subtract (lambda (x y) (- y x)))
(reverse-subtract 7 10)=> 3
(define add4 (let ((x 4)) (lambda (y) (+ x y))))
(add4 6)=> 10
The procedure takes a fixed number of arguments; when the procedure is called, the arguments are stored in the bindings of the corresponding variables.
The procedure takes any number of arguments; when the procedure is called, the sequence of arguments is converted into a newly allocated list, and the list is stored in the binding of the <variable>.
If a period . precedes the last variable, then the procedure takes
n or more arguments, where n is the number of parameters before
the period (there must be at least one). The value stored in the binding of
the last variable is a newly allocated list of the arguments left over after
all the other arguments have been matched up against the other
parameters.
((lambda x x) 3 4 5 6)=> (3 4 5 6)
((lambda (x y . z) z) 3 4 5 6)=> (5 6)
:optional, :key or :rest.
The <extended-spec> part consists of the optional argument spec, the
keyword argument spec and the rest argument spec. They can appear in any
combinations.
:optional optspec ...
variable
(variable init-expr)The variable names the formal argument, which is bound to the value of the actual argument if given, or the value of the expression init-expr otherwise. If optspec is just a variable, and the actual argument is not given, then it will be unspecified value. The expression init-expr is only evaluated if the actual argument is not given. The scope in which init-expr is evaluated includes the preceding formal arguments.
((lambda (a b :optional (c (+ a b))) (list a b c)) 1 2)=> (1 2 3)
((lambda (a b :optional (c (+ a b))) (list a b c)) 1 2 -1)=> (1 2 -1)
((lambda (a b :optional c) (list a b c)) 1 2)=> (1 2 #<unspecified>)
((lambda (:optional (a 0) (b (+ a 1))) (list a b)))=> (1 2)
&serious if more actual arguments than the
number of required and optional arguments are given, unless it also has
:key or :rest arguments spec.
((lambda (:optional a b) (list a b)) 1 2 3)=> &serious
((lambda (:optional a b :rest r) (list a b r)) 1 2 3)=> (1 2 (3))
:key keyspec ... [:allow-other-keys [variable]]
variable
(variable init-expr)
((keyword variable) init-expr)
(variable keyword init-expr)The variable names the formal argument, which is bound to the actual argument given with the keyword of the same name as variable. When the actual is not given, init-expr is evaluated and the result is bound to variable in the second, third and fourth form, or unspecified value is bound in the first form.
(define f (lambda (a :key (b (+ a 1)) (c (+ b 1)))
(list a b c)))
(f 10)=> (10 11 12)
(f 10 :b 4)=> (10 4 5)
(f 10 :c 8)=> (10 11 8)
(f 10 :c 1 :b 3)=> (10 3 1)
((lambda (:key ((:aa a) -1)) a) ::aa 2)=> 2
((lambda (:key (a :aa -1)) a) ::aa 2)=> 2
&serious if a keyword argument with an unrecognized keyword is
given. Giving :allow-other-keys in the formals suppresses this
behaviour. If you give variable after :allow-other-keys, the
list of unrecognized keywords and their arguments are bound to it.
((lambda (:key a) a) :a 1 :b 2)=> &serious
((lambda (:key a :allow-other-keys) a) :a 1 :b 2)=> 1
((lambda (:key a :allow-other-keys z) (list a z)) :a 1 :b 2)=> (1 (b 2))
:optional argument spec, the keyword arguments are
searched after all the optional arguments are bound.
((lambda (:optional a b :key c) (list a b c)) 1 2 :c 3)=> (1 2 3)
((lambda (:optional a b :key c) (list a b c)) :c 3)=> (c 3 #<unspecified>)
((lambda (:optional a b :key c) (list a b c)) 1 :c 3)=> &serious
:rest variable
:optional
argument spec, a list of remaining arguments after required arguments are
taken is bound to variable. If specified with :optional
argument spec, the actual arguments are first bound to required and all
optional arguments, and the remaining arguments are bound to
variable.
((lambda (a b :rest z) (list a b z)) 1 2 3 4 5)=> (1 2 (3 4 5))
((lambda (a b :optional c d :rest z) (list a b z)) 1 2 3 4 5)=> (1 2 3 4 (5))
((lambda (a b :optional c d :rest z) (list a b z)) 1 2 3)=> (1 2 3 #<unspecified> ())
((lambda (:optional a :rest r :key k) (list a r k)) 1 :k 3)=> (1 (k 3) 3)
if expression is evaluated as follows: first, test
is evaluated. If it yields a true value, then consequent is evaluated and
its values are returned. Otherwise alternate is evaluated and its values
are returned. If test yields #f and no alternate is specified, then
the result of the expression is unspecified.
set! expression or at the top level. The result
of the set! expression is unspecified.
Note: R6RS requires to throw syntax violation if variable refers immutable
binding. In Sagittarius, however, it won't throw any error.
(test expression ...)
(test => expression)
(else expression ...)The last form can appear only in the last clause. A
cond expression is evaluated by evaluating the test expressions of
successive clauses in order until one of them evaluates to a true value.
When a test evaluates to a true value, then the remaining expressions in
its clause are evaluated in order, and the results of the last expression
in the clause are returned as the results of the entire cond expression.
If the selected clause contains only the test and no expressions,
then the value of the test is returned as the result. If the selected
clause uses the => alternate form, then the expression is evaluated.
Its value must be a procedure. This procedure should accept one argument; it is
called on the value of the test and the values returned by this procedure
are returned by the cond expression. If all tests evaluate to #f,
and there is no else clause, then the conditional expression returns
unspecified values; if there is an else clause, then its expressions are
evaluated, and the values of the last one are returned.
((datum ...) expression ...)
(else expression ...)The last form can appear only in the last clause. A
case expression is evaluated as follows. Key is evaluated and its
result is compared using eqv? against the data represented by the datums
of each clause in turn, proceeding in order from left to right through
the set of clauses. If the result of evaluating key is equivalent to a datum
of a clause, the corresponding expressions are evaluated from left to right
and the results of the last expression in the clause are returned as the
results of the case expression. Otherwise, the comparison process continues.
If the result of evaluating key is different from every datum in each set,
then if there is an else clause its expressions are evaluated and the
results of the last are the results of the case expression; otherwise the
case expression returns unspecified values.
(and (= 2 2) (> 2 1))=> #t
(and (= 2 2) (< 2 1))=> #f
(and 1 2 'c '(f g))=> (f g)
(and)=> #t
(or (= 2 2) (> 2 1))=> #t
(or (= 2 2) (< 2 1))=> #t
(or #f #f #f)=> #f
(or '(b c) (/ 3 0))=> (b c)
((variable1 init1) ...)where each init is an expression. Any variable must not appear more than once in the variables. The inits are evaluated in the current environment, the variables are bound to fresh locations holding the results, the body is evaluated in the extended environment, and the values of the last expression of body are returned. Each binding of a variable has body as its region.
((variable1 init1) ...)The
let* form is similar to let, but the inits are evaluated
and bindings created sequentially from left to right, with the region of each
binding including the bindings to its right as well as body. Thus the second
init is evaluated in an environment in which the first binding is visible
and initialized, and so on.
((variable1 init1) ...)where each init is an expression. Any variable must not appear more than once in the variables. The variables are bound to fresh locations, the inits are evaluated in the resulting environment, each variable is assigned to the result of the corresponding init, the body is evaluated in the resulting environment, and the values of the last expression in body are returned. Each binding of a variable has the entire
letrec expression as its region, making it
possible to define mutually recursive procedures.
In the most common uses of letrec, all the inits are lambda
expressions and the restriction is satisfied automatically.
((variable1 init1) ...)where each init is an expression. Any variable must not appear more than once in the variables. The variables are bound to fresh locations, each variable is assigned in left-to-right order to the result of evaluating the corresponding init, the body is evaluated in the resulting environment, and the values of the last expression in body are returned. Despite the left-to-right evaluation and assignment order, each binding of a variable has the entire
letrec*
expression as its region, making it possible to define mutually recursive procedures.
((formals init1) ...)where each init is an expression. Any variable must not appear more than once in the set of formals. The inits are evaluated in the current environment, and the variables occurring in the formals are bound to fresh locations containing the values returned by the inits, where the formals are matched to the return values in the same way that the formals in a
lambda expression are
matched to the arguments in a procedure call. Then, the body is evaluated
in the extended environment, and the values of the last expression of body
are returned. Each binding of a variable has body as its region. If the
formals do not match, an exception with condition type &assertion
is raised.
((formals init1) ...)where each init is an expression. In each formals, any variable must not appear more than once. The
let*-values form is similar to let-values, but the inits
are evaluated and bindings created sequentially from left to right, with the
region of the bindings of each formals including the bindings to its right
as well as body. Thus the second init is evaluated in an environment
in which the bindings of the first formals is visible and initialized, and
so on.
predicate is a procedure that always returns a boolean value (#t or #f).
An equivalence predicate is the computational analogue of a mathematical
equivalence relation (it is symmetric, reflexive, and transitive). Of the
equivalence predicates described in this section, eq? is the finest or
most discriminating, and equal? is the coarsest. The eqv? predicate
is slightly less discriminating than eq?.
eq? only sees if the given two objects are the same object
or not, eqv? compares numbers. equal? compares the values
equivalence.
On Sagittarius Scheme interned symbol, keyword(only compatible mode), character,
literal string, boolean, fixnum, and '() are used as the same objects. If these
objects indicates the same value then eq? returns #t.
The following examples are not specified R6RS. But it is always good to know how
it works.
(let ((p (lambda (x) x))) (eqv? p p))=> #t
(eqv? "" "")=> #t
(eqv? "abc" "abc") ;; literal string are the same object=> #t
(eqv? "abc" (list->string '(#\a #\b #\c)))=> #f
(eqv? '#() '#())=> #f
(eqv? (lambda (x) x) (lambda (x) x))=> #f
(eqv? (lambda (x) x) (lambda (y) y))=> #f
(eqv? +nan.0 +nan.0)=> #f
(real? z) is true if and
only if (zero? (imag-part z)) and (exact? (imag-part z))
are both true.
If x is a real number object, then (rational? x) is true if
and only if there exist exact integer objects k1 and k2 such that
(= x (/ k1 k2)) and (= (numerator x) k1)
and (= (denominator x) k2) are all true. Thus infinities and
NaNs are not rational number objects.
If q is a rational number objects, then (integer? q) is true
if and only if (= (denominator q) 1) is true. If q is not a rational
number object, then (integer? q) is #f.
real-valued? procedure returns #t if the object is a number object and
is equal in the sense of = to some real number object, or if the object is
a NaN, or a complex number object whose real part is a NaN and whose imaginary part
is zero in the sense of zero?. The rational-valued? and integer-valued?
procedures return #t if the object is a number object and is equal in the sense
of = to some object of the named type, and otherwise they return #f.
inexact procedure returns an inexact representation of
z. If inexact number objects of the appropriate type have bounded precision,
then the value returned is an inexact number object that is nearest to the argument.
The exact procedure returns an exact representation of z. The value
returned is the exact number object that is numerically closest to the argument;
in most cases, the result of this procedure should be numerically equal to its argument.
zero? procedure tests if the number object is = to zero.
The positive? tests whether it is greater than zero.
The negative? tests whether it is less than zero.
The odd? tests whether it is odd.
The even? tests whether it is even
The finite? tests whether it is not an infinity and not a NaN.
The infinite? tests whether it is an infinity.
The nan? tests whether it is a NaN.
&assertion when the divisor was 0, on
Sagittarius, however, it returns NaN or infinite number when it is running with
compatible mode. In R6RS mode it raises &assertion.
&assertion is raised.
floor returns the largest integer object
not larger than x. The ceiling procedure returns the smallest
integer object not smaller than x. The truncate procedure returns
the integer object closest to x whose absolute value is not larger than
the absolute value of x. The round procedure returns the closest
integer object to x, rounding to even when x represents a number
halfway between two integers.
Although infinities and NaNs are not integer objects, these procedures return
an infinity when given an infinity as an argument, and a NaN when given a NaN.
rationalize procedure returns the a number object
representing the simplest rational number differing from x1 by no more than
x2. A rational number r1 is simpler than another rational number
r2 if r1 = p1/q1 and r2 = p2/q2 (in
lowest terms) and |p1| ≤ |p2| and |q1| ≤ |q2|. Thus 3/5
is simpler than 4/7. Although not all rationals are comparable in this ordering
(consider 2/7 and 3/5) any interval contains a rational number that is simpler
than every other rational number in that interval (the simpler 2/5 lies between
2/7 and 3/5). Note that 0 = 0/1 is the simplest rational of all.
exp procedure computes the base-e exponential of z.
The log procedure with a single argument computes the natural logarithm
of z (not the base-ten logarithm); (log z1 z2) computes
the base-z2 logarithm of z1.
The asin, acos, and atan procedures compute arcsine,
arccosine, and arctangent, respectively.
The two-argument variant of atan computes
(angle (make-rectangular x2 x1)).
(real-part z) is
positive. For other cases in which the first argument is zero, an unspecified
number object(+nan.0+nan.0i) is returned.
For an exact real number object z1 and an exact integer object z2,
(expt z1 z2) must return an exact result. For all other values
of z1 and z2, (expt z1 z2) may return an inexact
result, even when both z1 and z2 are exact.
(make-rectangular x1 x2) returns c, and
(make-polar x3 x4) returns c.
number->string procedure takes a number object and a radix
and returns as a string an external representation of the given number object in
the given radix such that
(let ((number z) (radix radix))
(eqv? (string->number
(number->string number radix)
radix)
number))
is true.
string->number
returns #f.
These number->string and string->number's resolutions of radix are
taken from Gauche.
cons. The car
and cdr fields are accessed by the procedures car and cdr.
Pairs are used primarily to represent lists. A list can be defined recursively as
either the empty list or a pair whose cdr is a list. More precisely, the set of
lists is defined as the smallest set X such that
(a b c . d)is equivalent to
(a . (b . (c . d)))Whether a given pair is a list depends upon what is stored in the cdr field.
eqv?) from every existing object.
car and cdr,
where for example caddr could be defined by
(define caddr (lambda (x) (car (cdr (cdr x))))). Arbitrary compositions, up to four deep, are provided. There are twenty-eight of these procedures in all.
list-tail procedure returns the subchain of pairs of
list obtained by omitting the first k elements. If fallback
is given and k is out of range, it returns fallback otherwise
&assertion is raised.
list-ref procedure returns the kth element of
list. If fallback is given and k is out of range, it returns
fallback otherwise &assertion is raised.
map procedure applies proc element-wise to
the elements of the lists and returns a list of the results, in order. The
order in which proc is applied to the elements of the lists is unspecified.
If multiple returns occur from map, the values returned by earlier returns
are not mutated. If the given lists are not the same length, when the
shortest list is processed the map will stop.
for-each procedure applies proc element-wise
to the elements of the lists for its side effects, in order from the first
elements to the last. The return values of for-each are unspecified. If
the given lists are not the same length, when the shortest list is
processed the for-each will stop.
char->integer returns its Unicode scalar value as an
exact integer object. For a Unicode scalar value sv, integer->char
returns its associated character.
#\space.
These are equivalence:
(make-string 10)=> (code (make-string 10 #\space))
string-ref procedure returns character. If a third
argument is given ant k is not a valid index, it returns fallback,
otherwise raises &assertion.
k of string using zero-origin indexing.
string=? procedure
returns #f.
string<? is the
lexicographic ordering on strings induced by the ordering char<? on
characters. If two strings differ in length but are the same up to the length of
the shorter string, the shorter string is considered to be lexicographically less
than the longer string.
(string-length string).
The substring procedure returns a newly allocated string formed from the
characters of string beginning with index start (inclusive) and ending with
index end (exclusive).
string->list procedure returns a newly allocated list of the
characters that make up the given string.
The list->string procedure returns a newly allocated string formed from
the characters in list.
The string->list and list->string procedures are inverses so far
as equal? is concerned.
If optional argument start and end are given, it restrict the
conversion range. It convert from start (inclusive) to end
(exclusive).
If only start is given, then the end is the length of given string.
string-for-each procedure applies proc element-wise to the
characters of the strings for its side effects, in order from the first
characters to the last. The return values of string-for-each are unspecified.
Analogous to for-each.
list.vector-ref procedure returns the contents of element
k of vector. If a third argument is given and k is not a valid
index, it returns fallback, otherwise raises &assertion.
vector-set!
procedure stores obj in element k of vector, and returns
unspecified values.
It raises &assertion when it attempt to modify immutable vector on R6RS
mode.
vector->list procedure returns a newly allocated list
of the objects contained in the elements of vector. The list->vector
procedure returns a newly created vector initialized to the elements of the list
list. The optional start and end arguments limit the range of
the source.
(vector->list '#(1 2 3 4 5))=> (1 2 3 4 5)
(list->vector '(1 2 3 4 5))=> #(1 2 3 4 5)
(vector->list '#(1 2 3 4 5) 2 4)=> (3 4)
(list->vector (circular-list 'a 'b 'c) 1 6)=> #(b c a b c)
vector-map procedure applies proc element-wise to the elements
of the vectors and returns a vector of the results, in order. If multiple
returns occur from vector-map, the return values returned by earlier
returns are not mutated.
Analogous to map.
vector-for-each procedure applies proc element-wise to the
elements of the vectors for its side effects, in order from the first
elements to the last. The return values of vector-for-each are unspecified.
Analogous to for-each.
error procedure should be called
when an error has occurred, typically caused by something that has gone wrong in
the interaction of the program with the external world or the user. The
assertion-violation procedure should be called when an invalid call to a
procedure was made, either passing an invalid number of arguments, or passing an
argument that it is not specified to handle.
The who argument should describe the procedure or operation that detected
the exception. The message argument should describe the exceptional situation.
The irritants should be the arguments to the operation that detected the
operation.
apply
procedure calls proc with the elements of the list
(append (list arg1 ...) rest-args) as the actual arguments.
If a call to apply occurs in a tail context, the call to proc is
also in a tail context.
call-with-current-continuation (which is the same as the procedure
call/cc) packages the current continuation as an "escape procedure" and
passes it as an argument to proc. The escape procedure is a Scheme procedure
that, if it is later called, will abandon whatever continuation is in effect a
that later time and will instead reinstate the continuation that was in effect
when the escape procedure was created. Calling the escape procedure may cause
the invocation of before and after procedures installed using
dynamic-wind.
The escape procedure accepts the same number of arguments as the continuation
of the original call to call-with-current-continuation.
call-with-values procedure calls producer
with no arguments and a continuation that, when passed some values, calls the
consumer procedure with those values as arguments. The continuation for
the call to consumer is the continuation of the call to call-with-values.
If a call to call-with-values occurs in a tail context, the call to
consumer is also in a tail context.
dynamic-wind procedure calls thunk without arguments,
returning the results of this call. Moreover, dynamic-wind calls before
without arguments whenever the dynamic extent of the call to thunk is
entered, and after without arguments whenever the dynamic extent of the
call to thunk is exited. Thus, in the absence of calls to escape procedures
created by call-with-current-continuation, dynamic-wind calls
before, thunk, and after, in that order.
let that provides
a general looping construct and may also be used to express recursion. It has
the same syntax and semantics as ordinary let except that variable
is bound within body to a procedure whose parameters are the bound variables
and whose body is body. Thus the execution of body may be repeated
by invoking the procedure named by variable.
unquote or unquote-splicing forms appear within the
qq-template, the result of evaluating (quasiquote qq-template)
is equivalent to the result of evaluating (quote qq-template).
If an (unquote expression ...) form appears inside a qq-template,
however, the expressions are evaluated ("unquoted") and their results are
inserted into the structure instead of the unquote form.
If an (unquote-splicing expression ...) form appears inside a
qq-template, then the expressions must evaluate to lists; the opening and
closing parentheses of the lists are then "stripped away" and the elements of
the lists are inserted in place of the unquote-splicing form.
Any unquote-splicing or multi-operand unquote form must appear only within
a list or vector qq-template.
Note: even though unquote and unquote-splicing are bounded, however
it does not work with import prefix nor renamed import. This may be fixed in future.
let-syntax and letrec-syntax forms bind keywords. On R6RS mode
it works like a begin form, a let-syntax or letrec-syntax
form may appear in a definition context, in which case it is treated as a
definition, and the forms in the body must also be definitions. A let-syntax
or letrec-syntax form may also appear in an expression context, in which
case the forms within their bodies must be expressions.
((keyword expression) ...)Each keyword is an identifier, and each expression is an expression that evaluates, at macro-expansion time, to a transformer. Transformers may be created by
syntax-rules or identifier-syntax or by one of the other
mechanisms described in library chapter on "syntax-case".
It is a syntax violation for keyword to appear more than once in the list
of keywords being bound.
The forms are expanded in the syntactic environment obtained by extending
the syntactic environment of the let-syntax form with macros whose keywords
are the keywords, bound to the specified transformers. Each binding of a
keyword has the forms as its region.
((keyword expression) ...)Each keyword is an identifier, and each expression is an expression that evaluates, at macro-expansion time, to a transformer. Transformers may be created by
syntax-rules or identifier-syntax or by one of the other
mechanisms described in library chapter on "syntax-case".
It is a syntax violation for keyword to appear more than once in the list
of keywords being bound.
The forms are expanded in the syntactic environment obtained by extending
the syntactic environment of the letrec-syntax form with macros whose
keywords are the keywords, bound to the specified transformers. Each
binding of a keyword has the bindings as well as the forms within its
region, so the transformers can transcribe forms into uses of the macros
introduced by the letrec-syntax form.
Note: The forms of a let-syntax and a letrec-syntax form are
treated, whether in definition or expression context, as if wrapped in an implicit
begin on R6RS mode, it is, then, treated as if wrapped in an implicit
let on compatible mode. Thus on compatible mode, it creates a scope.
'_' '...' as bounded symbols but in Sagittarius
these are not bound. And if import clause has rename or prefix these auxiliary
syntax are not be renamed or prefixed. This behaivour may be fixed in future.
(srpattern template)An srpattern is a restricted form of pattern, namely, a nonempty pattern in one of four parenthesized forms below whose first subform is an identifier or an underscore
_. A pattern is an identifier,
constant, or one of the following.
"..." (three periods).
A template is a pattern variable, an identifier that is not a pattern
variable, a pattern datum, or one of the following.
syntax-rules evaluates, at macro-expansion time, to a new
macro transformer by specifying a sequence of hygienic rewrite rules. A use of a
macro whose keyword is associated with a transformer specified by syntax-rules
is matched against the patterns contained in the rules, beginning with the
leftmost rule. When a match is found, the macro use is transcribed hygienically
according to the template. It is a syntax violation when no match is found.
syntax-rules.
When a keyword is bound to a transformer produced by the first form of
identifier-syntax, references to the keyword within the scope of the
binding are replaced by template.
(define p (cons 4 5))
(define-syntax p.car (identifier-syntax (car p)))
p.car=> 4
(set! p.car 15)=> &syntax exception
identifier-syntax permits the transformer
to determine what happens when set! is used. In this case, uses of the
identifier by itself are replaced by template1, and uses of set! with
the identifier are replaced by template2
(define p (cons 4 5))
(define-syntax p.car
(identifier-syntax
(_ (car p))
((set! _ e) (set-car! p e))))
(set! p.car 15)
p.car=> 15
p=> (15 5)
(rnrs unicode (6))library
provide access to some aspects of the Unicode semantics for characters and strings:
category information, case-independent comparisons, case mappings, and normalization.
Some of the procedures that operate on characters or strings ignore the difference
between upper case and lower case. These procedures have "-ci"
(for "case insensitive") embedded in their names.
char-downcase
returns that character. If the argument is a lower-case or title-case character,
and there is a single character that is its upper-case form, then char-upcase
returns that character. If the argument is a lower-case or upper-case character,
and there is a single character that is its title-case form, then char-titlecase
returns that character. If the argument is not a title-case character and there
is no single character that is its title-case form, then char-titlecase
returns the upper-case form of the argument. Finally, if the character has a
case-folded character, then char-foldcase returns that character. Otherwise
the character returned is the same as the argument. For Turkic characters İ (#\x130)
and ı (#\x131), char-foldcase behaves as the identity function; otherwise
char-foldcase is the same as char-downcase composed with
char-upcase.
char=?, etc., but operate on
the case-folded versions of the characters.
string=? to the argument, these procedures may return the argument
instead of a newly allocated string.
The string-upcase procedure converts a string to upper case;
string-downcase converts a string to lower case.
The string-foldcase procedure converts the string to its case-folded
counterpart, using the full case-folding mapping, but without the special
mappings for Turkic languages.
The string-titlecase procedure converts the first cased character of each
word via char-titlecase, and downcases all other cased characters.
If the optional argument start and end are given, these must be
exact integer and the procedures will first substring the given string with
range start and end then convert it.
string=?, etc., but operate
on the case-folded versions of the strings.
string=?
to the argument, these procedures may return the argument instead of a newly
allocated string.
(rnrs bytevectors (6))library provides a single type for blocks of binary
data with multiple ways to access that data. It deals with integers and
floating-point representations in various sizes with specified endianness.
Bytevectorsare objects of a disjoint type. Conceptually, a bytevector represents
a sequence of 8-bit bytes. The description of bytevectors uses the term byte for
an exact integer object in the interval { - 128, ..., 127} and the term octet for
an exact integer object in the interval {0, ..., 255}. A byte corresponds to its
two's complement representation as an octet.
The length of a bytevector is the number of bytes it contains. This number is
fixed. A valid index into a bytevector is an exact, non-negative integer object
less than the length of the bytevector. The first byte of a bytevector has index
0; the last byte has an index one less than the length of the bytevector.
Generally, the access procedures come in different flavors according to the size
of the represented integer and the endianness of the representation. The procedures
also distinguish signed and unsigned representations. The signed representations
all use two's complement.
Like string literals, literals representing bytevectors do not need to be quoted:
#vu8(12 23 123)=> #vu8(12 23 123)
(endianness symbol) evaluates to the symbol named symbol.
Whenever one of the procedures operating on bytevectors accepts an endianness as
an argument, that argument must be one of these symbols. It is a syntax violation
for symbol to be anything other than an endianness symbol supported by the Sagittarius.
Currently, Sagittarius supports these symbols; big, little
and native.
make-bytevector procedure. The bytevector-fill! procedure stores
fill in every element of bytevector and returns unspecified values.
Analogous to vector-fill!.
If optional arguments start or end is given, then the procedure
restricts the range of filling from start to end (exclusive) index
of bytevector. When end is omitted then it uses the length of the
given bytevector.
bytevector-copy! procedure copies the bytes from source at indices
source-start, ... source-start + k - 1
to consecutive indices in target starting at target-index.
This returns unspecified values.
bytevector-u8-ref procedure returns the byte at index k of
bytevector, as an octet.
The bytevector-s8-ref procedure returns the byte at index k of
bytevector, as a (signed) byte.
bytevector-u8-set! procedure stores octet in element k
of bytevector.
The bytevector-s8-set! procedure stores the two's-complement
representation of byte in element k of bytevector.
Both procedures return unspecified values.
bytevector->u8-list procedure returns a newly allocated list of the
octets of bytevector in the same order.
The u8-list->bytevector procedure returns a newly allocated bytevector
whose elements are the elements of list list, in the same order. It is
analogous to list->vector.
bytevector-uint-ref procedure retrieves the exact integer object
corresponding to the unsigned representation of size size and specified
by endianness at indices k, ..., k + size - 1.
The bytevector-sint-ref procedure retrieves the exact integer object
corresponding to the two's-complement representation of size size and
specified by endianness at indices k, ..., k + size - 1.
For bytevector-uint-set!, n must be an exact integer object in the
interval
The bytevector-uint-set! procedure stores the unsigned representation of
size size and specified by endianness into bytevector at indices
k, ..., k + size - 1.
For bytevector-sint-set!, n must be an exact integer object in the
interval .
bytevector-sint-set! stores the two's-complement representation of size
size and specified by endianness into bytevector at indices
k, ..., k + size - 1.
The ...-set! procedures return unspecified values.
uint-list->bytevector, list must be a list of exact integer objects
in the interval . For sint-list->bytevector,
list must be a list of exact integer objects in the interval
. The length of bytevector
or, respectively, of list must be divisible by size.
These procedures convert between lists of integer objects and their consecutive
representations according to size and endianness in the bytevector
objects in the same way as bytevector->u8-list and u8-list->bytevector
do for one-byte representations.
bytevector-u16-set! and bytevector-u16-native-set!, n
must be an exact integer object in the interval .
For bytevector-s16-set! and bytevector-s16-native-set!, n
must be an exact integer object in the interval .
These retrieve and set two-byte representations of numbers at indices k
and k + 1, according to the endianness specified by endianness.
The procedures with u16 in their names deal with the unsigned representation;
those with s16 in their names deal with the two's-complement representation.
The procedures with native in their names employ the native endianness,
and work only at aligned indices: k must be a multiple of 2.
The ...-set! procedures return unspecified values.
bytevector-u32-set! and bytevector-u32-native-set!, n
must be an exact integer object in the interval .
For bytevector-s32-set! and bytevector-s32-native-set!, n
must be an exact integer object in the interval .
These retrieve and set two-byte representations of numbers at indices k
and k + 3, according to the endianness specified by endianness.
The procedures with u32 in their names deal with the unsigned representation;
those with s32 in their names deal with the two's-complement representation.
The procedures with native in their names employ the native endianness,
and work only at aligned indices: k must be a multiple of 4.
The ...-set! procedures return unspecified values.
bytevector-u64-set! and bytevector-u64-native-set!, n
must be an exact integer object in the interval .
For bytevector-s64-set! and bytevector-s64-native-set!, n
must be an exact integer object in the interval .
These retrieve and set two-byte representations of numbers at indices k
and k + 7, according to the endianness specified by endianness.
The procedures with u64 in their names deal with the unsigned representation;
those with s64 in their names deal with the two's-complement representation.
The procedures with native in their names employ the native endianness,
and work only at aligned indices: k must be a multiple of 8.
The ...-set! procedures return unspecified values.
bytevector-ieee-single-native-ref, k must be a multiple of 4.
These procedures return the inexact real number object that best represents the
IEEE-754 single-precision number represented by the four bytes beginning at index
k.
bytevector-ieee-double-native-ref, k must be a multiple of 8.
These procedures return the inexact real number object that best represents the
IEEE-754 double-precision number represented by the four bytes beginning at index
k.
bytevector-ieee-single-native-set!, k must be a multiple of 4.
These procedures store an IEEE-754 single-precision representation of x
into elements k through k + 3 of bytevector, and return
unspecified values.
bytevector-ieee-double-native-set!, k must be a multiple of 8.
These procedures store an IEEE-754 double-precision representation of x
into elements k through k + 7 of bytevector, and return
unspecified values.
big
or the symbol little. The string->utf16 procedure returns a newly
allocated (unless empty) bytevector that contains the UTF-16BE or UTF-16LE
encoding of the given string (with no byte-order mark). If endianness
is not specified or is big, then UTF-16BE is used. If endianness is
little, then UTF-16LE is used.
big
or the symbol little. The string->utf32 procedure returns a newly
allocated (unless empty) bytevector that contains the UTF-32BE or UTF-32LE
encoding of the given string (with no byte-order mark). If endianness
is not specified or is big, then UTF-32BE is used. If endianness is
little, then UTF-32LE is used.
big or the symbol
little. The utf16->string procedure returns a newly allocated
(unless empty) string whose character sequence is encoded by the given
bytevector. Bytevector is decoded according to UTF-16BE or UTF-16LE:
If endianness-mandatory? is absent or #f, utf16->string determines
the endianness according to a UTF-16 BOM at the beginning of bytevector
if a BOM is present; in this case, the BOM is not decoded as a character. Also
in this case, if no UTF-16 BOM is present, endianness specifies the endianness
of the encoding. If endianness-mandatory? is a true value, endianness
specifies the endianness of the encoding, and any UTF-16 BOM in the encoding is
decoded as a regular character.
big or the symbol
little. The utf32->string procedure returns a newly allocated
(unless empty) string whose character sequence is encoded by the given
bytevector. Bytevector is decoded according to UTF-32BE or UTF-32LE:
If endianness-mandatory? is absent or #f, utf32->string determines
the endianness according to a UTF-32 BOM at the beginning of bytevector
if a BOM is present; in this case, the BOM is not decoded as a character. Also
in this case, if no UTF-32 BOM is present, endianness specifies the endianness
of the encoding. If endianness-mandatory? is a true value, endianness
specifies the endianness of the encoding, and any UTF-32 BOM in the encoding is
decoded as a regular character.
(rnrs lists (6))library, which contains various useful
procedures that operate on lists.
find procedure applies proc
to the elements of list in order. If proc returns a true value for
an element, find immediately returns that element. If proc returns #f for
all elements of the list, find returns #f.
for-all returns the last result of the applications.
for-all and exists.
On Sagittarius, however, these can accept different length list and it will
finish to process when the shortest list is finish to process.
filter procedure applies proc to each element of list and
returns a list of the elements of list for which proc returned a true
value. The partition procedure also applies proc to each element of
list, but returns two values, the first one a list of the elements of list
for which proc returned a true value, and the second a list of the elements
of list for which proc returned #f. In both cases, the elements of the
result list(s) are in the same order as they appear in the input list. If multiple
returns occur from filter or partitions, the return values returned
by earlier returns are not mutated.
fold-left procedure iterates the combine
procedure over an accumulator value and the elements of the lists from left
to right, starting with an accumulator value of nil. More specifically,
fold-left returns nil if the lists are empty. If they are not
empty, combine is first applied to nil and the respective first
elements of the lists in order. The result becomes the new accumulator
value, and combine is applied to the new accumulator value and the respective
next elements of the list. This step is repeated until the end of the
list is reached; then the accumulator value is returned.
fold-right procedure iterates the
combine procedure over the elements of the lists from right to left
and an accumulator value, starting with an accumulator value of nil. More
specifically, fold-right returns nil if the lists are empty. If they
are not empty, combine is first applied to the respective last elements of
the lists in order and nil. The result becomes the new accumulator
value, and combine is applied to the respective previous elements of the
lists and the new accumulator value. This step is repeated until the beginning
of the list is reached; then the accumulator value is returned.
Note: R6RS requires the same length list for fold-left and fold-right.
On Sagittarius, however, these can accept different length list and it will finish
to process when the shortest list is finish to process.
remp procedure applies proc to each
element of list and returns a list of the elements of list for which
proc returned #f. The remove, remq procedures
return a list of the elements that are not obj. The remq procedure
uses eq? to compare obj with the elements of list, while
remv uses eqv? and remove uses equal?. The elements
of the result list are in the same order as they appear in the input list. If
multiple returns occur from remp, the return values returned by earlier
returns are not mutated.
(list-tail list k) for k less than the length of list.
The memp procedure applies proc to the cars of the sublists of
list until it finds one for which proc returns a true value. The
member, memv, and memq procedures look for the first
occurrence of obj. If list does not contain an element satisfying the
condition, then #f (not the empty list) is returned. The member procedure
uses equal? or if = is given use it to compare obj with the
elements of list, while memv uses eqv? and memq uses
eq?.
assp procedure successively applies proc to the car fields of
alist and looks for a pair for which it returns a true value. The
assoc, assv, and assq procedures look for a pair that has
obj as its car. The assoc procedure uses equal? or if =
is given use it to compare obj with the car fields of the pairs in alist,
while assv uses eqv? and assq uses member and assoc procedures are the same behaviour as SRFI-1.
list, but the last argument provides the tail of the
constructed list.(rnrs sorting (6))library provides procedures for sorting lists
and vectors.list-sort and vector-sort procedures perform a stable sort
of list or vector in ascending order according to proc, without
changing list or vector in any way. The list-sort procedure
returns a list, and vector-sort returns a vector. The results may be
eq? to the argument when the argument is already sorted, and the result
of list-sort may share structure with a tail of the original list. The
sorting algorithm performs O(n lg n) calls to proc where n is the length
of list or vector, and all arguments passed to proc are
elements of the list or vector being sorted, but the pairing of
arguments and the sequencing of calls to proc are not specified. If
multiple returns occur from list-sort or vector-sort, the
return values returned by earlier returns are not mutated.
If the optional argument start and end for vector-sort
is specified, then the sorting range is restricted by the given start
(inclusive) and end (exclusive).
vector-sort! procedure destructively sorts vector in
ascending order according to proc.
If the optional argument start and end is specified, then
the sorting range is restricted by the given start (inclusive)
and end (exclusive).
(rnrs control (6))library, which provides useful control structures.when expression is evaluated by evaluating the test expression.
If test evaluates to a true value, the remaining expressions are
evaluated in order, and the results of the last expression are returned as
the results of the entire when expression. Otherwise, the when
expression returns unspecified values. An unless expression is evaluated
by evaluating the test expression. If test evaluates to #f, the
remaining expressions are evaluated in order, and the results of the last
expression are returned as the results of the entire unless
expression. Otherwise, the unless expression returns unspecified values.
do expression is an iteration construct. It specifies a set of variables
to be bound, how they are to be initialized at the start, and how they are to be
updated on each iteration.
A do expression is evaluated as follows: The init expressions are
evaluated (in some unspecified order), the variables are bound to fresh
locations, the results of the init expressions are stored in the bindings
of the variables, and then the iteration phase begins.
Each iteration begins by evaluating test if the result is #f, then the
commands are evaluated in order for effect, the step expressions are
evaluated in some unspecified order, the variables are bound to fresh
locations holding the results, and the next iteration begins.
If test evaluates to a true value, the expressions are evaluated from
left to right and the values of the last expression are returned. If no
expressions are present, then the do expression returns unspecified
values.
The region of the binding of a variable consists of the entire do
expression except for the inits.
A step may be omitted, in which case the effect is the same as if
(variable init variable) had been written instead of
(variable init).
(do ((vec (make-vector 5))
(i 0 (+ i 1)))
((= i 5) vec)
(vector-set! vec i i))
=>
#(0 1 2 3 4)
(let ((x '(1 3 5 7 9)))
(do ((x x (cdr x))
(sum 0 (+ sum (car x))))
((null? x) sum)))
=>
25
(formals body)Formals must be as in a
lambda form.
A case-lambda expression evaluates to a procedure. This procedure, when
applied, tries to match its arguments to the case-lambda-clauses in order.
The arguments match a clause if one of the following conditions is fulfilled:
Formals has the form (variable ...) and the number of
arguments is the same as the number of formal parameters in formals.
Formals has the form
(variable1 ... variablen . variablen+1)and the number of arguments is at least n. Formals has the form variable. For the first clause matched by the arguments, the variables of the formals are bound to fresh locations containing the argument values in the same arrangement as with
lambda.
The last expression of a body in a case-lambda expression is in tail context.
If the arguments match none of the clauses, an exception with condition type
&assertion is raised.
(rnrs records syntactic (6))library. Some details of the
specification are explained in terms of the specification of the procedural
layer below.
define-record-type form defines a record type along with
associated constructor descriptor and constructor, predicate, field accessors,
and field mutators. The define-record-type form expands into a set of
definitions in the environment where define-record-type appears; hence,
it is possible to refer to the bindings (except for that of the record type
itself) recursively.
The name-spec specifies the names of the record type, constructor, and
predicate. It must take one of the following forms:
(record-name constructor-name predicate-name)
record-nameRecord-name, constructor-name, and predicate-name must all be identifiers. Record-name, taken as a symbol, becomes the name of the record type. (See the description of
protocol clause, or,
in its absence, using a default protocol. For details, see the description of the
protocol clause below.
Predicate-name is defined by this definition to a predicate for the defined
record type.
The second form of name-spec is an abbreviation for the first form, where
the name of the constructor is generated by prefixing the record name with
make-, and the predicate name is generated by adding a question mark
(?) to the end of the record name. For example, if the record name is
frob, the name of the constructor is make-frob, and the predicate
name is frob?
.
Each record-clause must take one of the auxiliary syntax forms; it is a
syntax violation if multiple record-clauses of the same kind appear in a
define-record-type form.
(fields field-spec*)Each field-spec has one of the following forms
(immutable field-name accessor-name)
(mutable field-name accessor-name mutator-name)
(immutable field-name)
(mutable field-name)
field-nameField-name, accessor-name, and mutator-name must all be identifiers. The first form declares an immutable field called field-name>, with the corresponding accessor named accessor-name. The second form declares a mutable field called field-name, with the corresponding accessor named accessor-name, and with the corresponding mutator named mutator-name. If field-spec takes the third or fourth form, the accessor name is generated by appending the record name and field name with a hyphen separator, and the mutator name (for a mutable field) is generated by adding a
-set! suffix to the
accessor name. For example, if the record name is frob and the field name
is widget, the accessor name is frob-widget and the mutator name is
frob-widget-set!.
If field-spec is just a field-name form, it is an abbreviation for
(immutable field-name).
The field-names become, as symbols, the names of the fields in the
record-type descriptor being created, in the same order.
The fields clause may be absent; this is equivalent to an empty fields
clause.
(parent parent-name)Specifies that the record type is to have parent type parent-name, where parent-name is the record-name of a record type previously defined using
define-record-type. The record-type definition associated with
parent-name must not be sealed. If no parent clause and no parent-rtd
(see below) clause is present, the record type is a base type.
(protocol expression)Expression is evaluated in the same environment as the
define-record-type
form, and must evaluate to a protocol appropriate for the record type being defined.
The protocol is used to create a record-constructor descriptor as described below.
If no protocol clause is specified, a constructor descriptor is still created
using a default protocol. The clause can be absent only if the record type being
defined has no parent type, or if the parent definition does not specify a protocol.
(sealed boolean)If this option is specified with operand #t, the defined record type is sealed, i.e., no extensions of the record type can be created. If this option is specified with operand #f, or is absent, the defined record type is not sealed.
(opaque boolean)If this option is specified with operand #t, or if an opaque parent record type is specified, the defined record type is opaque. Otherwise, the defined record type is not opaque. See the specification of record-rtd below for details.
(nongenerative uid)
(nongenerative)This specifies that the record type is nongenerative with uid uid, which must be an identifier. If uid is absent, a unique uid is generated at macro-expansion time. If two record-type definitions specify the same uid, then the record-type definitions should be equivalent, i.e., the implied arguments to
make-record-type-descriptor must be equivalent as described under
make-record-type-descriptor. If this condition is not met, it is either
considered a syntax violation or an exception with condition type &assertion
is raised. If the condition is met, a single record type is generated for both
definitions.
In the absence of a nongenerative clause, a new record type is generated
every time a define-record-type form is evaluated:
(let ((f (lambda (x)
(define-record-type r ...)
(if x r? (make-r ...)))))
((f #t) (f #f)))
=>
#f
(parent-rtd parent-rtd parent-cd)Specifies that the record type is to have its parent type specified by parent-rtd, which should be an expression evaluating to a record-type descriptor, and parent-cd, which should be an expression evaluating to a constructor descriptor. The record-type definition associated with the value of parent-rtd must not be sealed. Moreover, a record-type definition must not have both a
parent and a parent-rtd clause.
All bindings created by define-record-type (for the record type, the
constructor, the predicate, the accessors, and the mutators) must have names that
are pairwise distinct.
The constructor created by a define-record-type form is a procedure as
follows:
parent clause and no protocol clause, the
constructor accepts as many arguments as there are fields, in the same order
as they appear in the fields clause, and returns a record object with
the fields initialized to the corresponding arguments.parent or parent-rtd clause and a protocol
clause, the protocol expression must evaluate to a procedure that accepts a
single argument. The protocol procedure is called once during the evaluation of
the define-record-type form with a procedure p as its argument. It
should return a procedure, which will become the constructor bound to
constructor-name. The procedure p accepts as many arguments as there
are fields, in the same order as they appear in the fields clause, and returns
a record object with the fields initialized to the corresponding arguments.
The constructor returned by the protocol procedure can accept an arbitrary number
of arguments, and should call p once to construct a record object, and
return that record object.
For example, the following protocol expression for a record-type definition with
three fields creates a constructor that accepts values for all fields, and
initialized them in the reverse order of the arguments:
(lambda (p)
(lambda (v1 v2 v3)
(p v3 v2 v1)))
parent clause and a protocol clause, then
the protocol procedure is called once with a procedure nas its argument.
As in the previous case, the protocol procedure should return a procedure, which
will become the constructor bound to constructor-name. However, n is
different from p in the previous case: It accepts arguments corresponding
to the arguments of the constructor of the parent type. It then returns a procedure
p that accepts as many arguments as there are (additional) fields in this
type, in the same order as in the fields clause, and returns a record object
with the fields of the parent record types initialized according to their constructors
and the arguments to n, and the fields of this record type initialized to
its arguments of p.
The constructor returned by the protocol procedure can accept an arbitrary number
of arguments, and should call n once to construct the procedure p,
and call p once to create the record object, and finally return that record
object.
For example, the following protocol expression assumes that the constructor of
the parent type takes three arguments:
(lambda (n)
(lambda (v1 v2 v3 x1 x2 x3 x4)
(let ((p (n v1 v2 v3)))
(p x1 x2 x3 x4))))
The resulting constructor accepts seven arguments, and initializes the fields of
the parent types according to the constructor of the parent type, with v1,
v2, and v3 as arguments. It also initializes the fields of this
record type to the values of x1, ..., x4.
parent clause, but no protocol clause, then the
parent type must not have a protocol clause itself. The constructor bound
to constructor-name is a procedure that accepts arguments corresponding to
the parent types' constructor first, and then one argument for each field in the
same order as in the fields clause. The constructor returns a record object
with the fields initialized to the corresponding arguments.
parent-rtd clause, then the constructor is as with a
parent clause, except that the constructor of the parent type is determined
by the constructor descriptor of the parent-rtd clause.
(define-record-type frob
(fields (mutable widget))
(protocol
(lambda (p)
(lambda (n) (p (make-widget n))))))
is equivalent to the following explicit-naming record definition.
(define-record-type (frob make-frob frob?)
(fields (mutable widget
frob-widget
frob-widget-set!))
(protocol
(lambda (p)
(lambda (n) (p (make-widget n))))))
Also, the implicit-naming record definition:
(define-record-type point (fields x y))is equivalent to the following explicit-naming record definition:
(define-record-type (point make-point point?)
(fields
(immutable x point-x)
(immutable y point-y)))
With implicit naming, it is still possible to specify some of the names explicitly;
for example, the following overrides the choice of accessor and mutator names for
the widget field.
(define-record-type frob
(fields (mutable widget getwid setwid!))
(protocol
(lambda (p)
(lambda (n) (p (make-widget n))))))
record? procedure from the
(rnrs records inspection (6)) library:
(define-record-type (point make-point point?)
(fields (immutable x point-x)
(mutable y point-y set-point-y!))
(nongenerative point-4893d957-e00b-11d9-817f-00111175eb9e))
(define-record-type (cpoint make-cpoint cpoint?)
(parent point)
(protocol (lambda (n)
(lambda (x y c)
((n x y) (color->rgb c)))))
(fields (mutable rgb cpoint-rgb cpoint-rgb-set!)))
(define (color->rgb c) (cons 'rgb c))
(define p1 (make-point 1 2))
(define p2 (make-cpoint 3 4 'red))
(point? p1)=> #t
(point? p2)=> #t
(point? (vector))=> #f
(point? (cons 'a 'b))=> #f
(cpoint? p1)=> #f
(cpoint? p2)=> #t
(point-x p1)=> 1
(point-y p1)=> 2
(point-x p2)=> 3
(point-y p2)=> 4
(cpoint-rgb p2)=> (rgb . red)
(set-point-y! p1 17)=> unspecified
(point-y p1)=> 17
(record-rtd p1)=> (record-type-descriptor point)
(define-record-type (ex1 make-ex1 ex1?) (protocol (lambda (p) (lambda a (p a)))) (fields (immutable f ex1-f)))
(define ex1-i1 (make-ex1 1 2 3))
(ex1-f ex1-i1)=> (1 2 3)
(define-record-type (ex2 make-ex2 ex2?)
(protocol
(lambda (p) (lambda (a . b) (p a b))))
(fields (immutable a ex2-a)
(immutable b ex2-b)))
(define ex2-i1 (make-ex2 1 2 3))
(ex2-a ex2-i1)=> 1
(ex2-b ex2-i1)=> (2 3)
(define-record-type (unit-vector make-unit-vector unit-vector?)
(protocol (lambda (p)
(lambda (x y z)
(let ((length (sqrt (+ (* x x) (* y y) (* z z)))))
(p (/ x length) (/ y length) (/ z length))))))
(fields (immutable x unit-vector-x)
(immutable y unit-vector-y)
(immutable z unit-vector-z)))
(define *ex3-instance* #f)
(define-record-type ex3
(parent cpoint)
(protocol (lambda (n)
(lambda (x y t)
(let ((r ((n x y 'red) t)))
(set! *ex3-instance* r)
r))))
(fields (mutable thickness))
(sealed #t) (opaque #t))
(define ex3-i1 (make-ex3 1 2 17))
(ex3? ex3-i1)=> #t
(cpoint-rgb ex3-i1)=> (rgb . red)
(ex3-thickness ex3-i1)=> 17
(ex3-thickness-set! ex3-i1 18)=> unspecified
(ex3-thickness ex3-i1)=> 18
*ex3-instance*=> ex3-i1
(record? ex3-i1)=> #f
(rnrs records procedural (6))
library.
&assertion is raised if parent is sealed
(see below).
The uid argument must be either #f or a symbol. If uid is a symbol,
the record-creation operation is nongenerative i.e., a new record type is created
only if no previous call to make-record-type-descriptor was made with the
uid. If uid is #f, the record-creation operation is generative,
.e., a new record type is created even if a previous call to
make-record-type-descriptor was made with the same arguments.
If make-record-type-descriptor is called twice with the same uid
symbol, the parent arguments in the two calls must be eqv?, the
fields arguments equal?, the sealed? arguments boolean-equivalent
(both #f or both true), and the opaque? arguments boolean-equivalent. If
these conditions are not met, an exception with condition type &assertion
is raised when the second call occurs. If they are met, the second call returns,
without creating a new record type, the same record-type descriptor (in the
sense of eqv?) as the first call.
The sealed? flag must be a boolean. If true, the returned record type is
sealed, i.e., it cannot be extended.
The opaque? flag must be a boolean. If true, the record type is opaque. If
passed an instance of the record type, record? returns #f. Moreover, if
record-rtd (see (rnrs records inspection (6)))
is called with an instance of the record type, an exception with condition
type &assertion is raised. The record type is also opaque if an opaque
parent is supplied. If opaque? is #f and an opaque parent is not supplied,
the record is not opaque.
The fields argument must be a vector of field specifiers. Each field specifier
must be a list of the form (mutable name) or a list of the form
(immutable name). Each name must be a symbol and names the corresponding
field of the record type; the names need not be distinct. A field identified as
mutable may be modified, whereas, when a program attempts to obtain a mutator for
a field identified as immutable, an exception with condition type &assertion
is raised. Where field order is relevant, e.g., for record construction and field
access, the fields are considered to be ordered as specified, although no particular
order is required for the actual representation of a record instance.
The specified fields are added to the parent fields, if any, to determine the
complete set of fields of the returned record type. If fields is modified after
make-record-type-descriptor has been called, the effect on the returned
rtd is unspecified.
A generative record-type descriptor created by a call to
make-record-type-descriptor is not eqv? to any record-type descriptor
(generative or nongenerative) created by another call to
make-record-type-descriptor. A generative record-type descriptor is eqv?
only to itself, i.e., (eqv? rtd1 rtd2) iff (eq? rtd1 rtd2). Also, two nongenerative
record-type descriptors are eqv? if they were created by calls to
make-record-type-descriptor with the same uid arguments.
record-constructor.
A constructor descriptor can also be used to create other constructor descriptors
for subtypes of its own record type. Rtd must be a record-type descriptor.
Protocol must be a procedure or #f. If it is #f, a default protocol procedure
is supplied.
If protocol is a procedure, it is handled analogously to the protocol
expression in a define-record-type form.
If rtd is a base record type and protocol is a procedure,
parent-constructor-descriptor must be #f. In this case, protocol
is called by record-constructor with a single argument p. P
is a procedure that expects one argument for every field of rtd and returns
a record with the fields of rtd initialized to these arguments. The
procedure returned by protocol should call p once with the number of
arguments p expects and return the resulting record as shown in the
simple example below:
(lambda (p)
(lambda (v1 v2 v3)
(p v1 v2 v3)))
Here, the call to p returns a record whose fields are initialized with
the values of v1, v2, and v3. The expression above is
equivalent to (lambda (p) p). Note that the procedure returned by protocol
is otherwise unconstrained; specifically, it can take any number of arguments.
If rtd is an extension of another record type parent-rtd and
protocol is a procedure, parent-constructor-descriptor must be a
constructor descriptor of parent-rtd or #f. If
parent-constructor-descriptor is a constructor descriptor, protocol
it is called by record-constructor with a single argument n, which
is a procedure that accepts the same number of arguments as the constructor of
parent-constructor-descriptor and returns a procedure p that, when
called, constructs the record itself. The p procedure expects one argument
for every field of rtd (not including parent fields) and returns a record
with the fields of rtd initialized to these arguments, and the fields of
parent-rtd and its parents initialized as specified by
parent-constructor-descriptor.
The procedure returned by protocol should call n once with the number
of arguments n expects, call the procedure p it returns once with
the number of arguments p expects and return the resulting record. A
simple protocol in this case might be written as follows:
(lambda (n)
(lambda (v1 v2 v3 x1 x2 x3 x4)
(let ((p (n v1 v2 v3)))
(p x1 x2 x3 x4))))
This passes arguments v1, v2, v3 to n for
parent-constructor-descriptor and calls p with x1, ...,
x4 to initialize the fields of rtd itself.
Thus, the constructor descriptors for a record type form a sequence of protocols
parallel to the sequence of record-type parents. Each constructor descriptor in
the chain determines the field values for the associated record type. Child record
constructors need not know the number or contents of parent fields, only the number
of arguments accepted by the parent constructor.
Protocol may be #f, specifying a default constructor that accepts one
argument for each field of rtd (including the fields of its parent type,
if any). Specifically, if rtd is a base type, the default protocol procedure
behaves as if it were (lambda (p) p). If rtd is an extension of
another type, then parent-constructor-descriptor must be either #f or
itself specify a default constructor, and the default protocol procedure behaves
as if it were:
(lambda (n)
(lambda (v1 ... vj x1 ... xk)
(let ((p (n v1 ... vj)))
(p x1 ... xk))))
The resulting constructor accepts one argument for each of the record type's complete
set of fields (including those of the parent record type, the parent's parent record
type, etc.) and returns a record with the fields initialized to those arguments,
with the field values for the parent coming before those of the extension in the
argument list. (In the example, j is the complete number of fields of the
parent type, and k is the number of fields of rtd itself.)
If rtd is an extension of another record type, and parent-constructor-descriptor
or the protocol of parent-constructor-descriptor is #f, protocol must
also be #f, and a default constructor descriptor as described above is also assumed.
make-record-constructor-descriptor) and returns the resulting constructor
constructor for records of the record type associated with
constructor-descriptor.
record-accessor procedure returns a one-argument procedure whose argument
must be a record of the type represented by rtd. This procedure returns
the value of the selected field of that record.
The field selected corresponds to the kth element (0-based) of the fields
argument to the invocation of make-record-type-descriptor that created
rtd. Note that k cannot be used to specify a field of any type
rtd extends.
record-mutator procedure returns a two-argument procedure whose arguments
must be a record record r of the type represented by rtd and an
object obj. This procedure stores obj within the field of r
specified by k. The k argument is as in record-accessor. If
k specifies an immutable field, an exception with condition type
&assertion is raised. The mutator returns unspecified values.
(rnrs records inspection (6))library provides procedures for
inspecting records and their record-type descriptors. These procedures are designed
to allow the writing of portable printers and inspectors.
&assertion.
make-record-type-descriptor.
record-accessor.
(rnrs exceptions (6))library.
with-exception-handler procedure returns the results of invoking
thunk. When an exception is raised, handler will be invoked with
the exception.
cond.
and else are the same as in the (rnrs base (6)) library.
Evaluating a guard form evaluates body with an exception handler
that binds the raised object to variable and within the scope of that
binding evaluates the clauses as if they were the clauses of a cond
expression. If every cond-clause's test evaluates to #f and there is
no else clause, then raise is re-invoked on the raised object.
(rnrs conditions (6))library for creating and
inspecting condition types and values. A condition value encapsulates information
about an exceptional situation.
condition procedure returns a condition object with the
components of the conditions as its components, in the same order. The
returned condition is compound if the total number of components is zero or
greater than one. Otherwise, it may be compound or simple.
simple-conditions procedure returns a list of the
components of condition, in the same order as they appeared in the
construction of condition.
&condition. The condition-predicate procedure returns a procedure
that takes one argument. This procedure returns #t if its argument is a condition
of the condition type represented by rtd, i.e., if it is either a simple
condition of that record type (or one of its subtypes) or a compound conditition
with such a simple condition as one of its components, and #f otherwise.
&condition. Proc should accept one argument, a record of the
record type of rtd. The condition-accessor procedure returns a
procedure that accepts a single argument, which must be a condition of the type
represented by rtd. This procedure extracts the first component of the
condition of the type represented by rtd, and returns the result of
applying proc to that component.
(field accessor)where both field and accessor must be identifiers. The
define-condition-type form expands into a record-type definition for
a record type condition-type. The record type will be non-opaque, non-sealed,
and its fields will be immutable. It will have supertype has its parent type.
The remaining identifiers will be bound as follows:
+ &condition
+ &warning
+ &serious
+ &error
+ &violation
+ &assertion
+ &non-continuable
+ &implementation-restriction
+ &lexical
+ &syntax
+ &undefined
+ &message
+ &irritants
error and assertion-violation procedures.error
and assertion-violation procedures, and the syntax-violation
procedure.(rnrs io ports (6)) and (rnrs io simple (6)) libraries.
They are also exported by the (rnrs files (6)) library.
&i/o-port-error
condition.+ &error(See (rnrs conditions (6))) + &i/o + &i/o-read + &i/o-write + &i/o-invalid-position + &i/o-filename + &i/o-file-protection + &i/o-file-is-read-only + &i/o-file-already-exists + &i/o-file-does-not-exist + &i/o-port-error
(rnrs io ports (6))library defines an I/O layer for
conventional, imperative buffered input and output. A port represents
a buffered access object for a data sink or source or both simultaneously.
The library allows ports to be created from arbitrary data sources and sinks.
The (rnrs io ports (6)) library distinguishes between input ports
and output ports. An input port is a source for data, whereas an output
port is a sink for data. A port may be both an input port and an output port;
such a port typically provides simultaneous read and write access to a file or
other data.
The (rnrs io ports (6)) library also distinguishes between
binary ports, which are sources or sinks for uninterpreted bytes,
and textual ports, which are sources or sinks for characters and strings.
This section uses input-port, output-port, binary-port,
textual-port, binary-input-port, textual-input-port,
binary-output-port, textual-output-port, and port as parameter
names for arguments that must be input ports (or combined input/output ports),
output ports (or combined input/output ports), binary ports, textual ports,
binary input ports, textual input ports, binary output ports, textual output
ports, or any kind of port, respectively.
file-options object that encapsulates flags to specify how the file is to
be opened. A file-options object is an enum-set
(see (rnrs enums (6))) over the symbols constituting
valid file options. A file-options parameter name means that the
corresponding argument must be a file-options object.
(file-options) specifies that the file is created if
it does not exist and an exception with condition type
&i/o-file-already-exists is raised if it does exist. The following
standard options can be included to modify the default behaviour.
no-create If the file does not already exist, it is not created;
instead, an exception with condition type &i/o-file-does-not-exist is
raised. If the file already exists, the exception with condition type
&i/o-file-already-exists is not raised and the file is truncated to zero
length.
no-fail If the file already exists, the exception with condition
type &i/o-file-already-exists is not raised, even if no-create is
not included, and the file is truncated to zero length.
no-truncate If the file already exists and the exception with
condition type &i/o-file-already-exists has been inhibited by inclusion
of no-create or no-fail, the file is not truncated, but the port's
current position is still set to the beginning of the file.
append Among with no-truncate, set the opened port's
position the end of the file. This is not a part of R6RS specification.
none, line, and block. The result is the corresponding
symbol, and specifies the associated buffer mode.
eqv? to the result of any other call to the same procedure.lf, cr, crlf, nel, crnel, ls, and
none. The form evaluates to the corresponding symbol. If the name of
eol-style-symbol is not one of these symbols, it still returns given
symbol, however make-transcoder does not accept it.
ignore, raise, and replace. The form evaluates to
the corresponding symbol.
The error-handling mode of a transcoder specifies the behavior of textual
I/O operations in the presence of encoding or decoding errors.
If a textual input operation encounters an invalid or incomplete character
encoding, and the error-handling mode is ignore, an appropriate number
of bytes of the invalid encoding are ignored and decoding continues with the
following bytes. If the error-handling mode is replace, the replacement
character U+FFFD is injected into the data stream, an appropriate number of
bytes are ignored, and decoding continues with the following bytes. If the
error-handling mode is raise, an exception with condition type
&i/o-decoding is raised.
If a textual output operation encounters a character it cannot encode, and the
error-handling mode is ignore, the character is ignored and encoding
continues with the next character. If the error-handling mode is replace,
a codec-specific replacement character is emitted by the transcoder, and
encoding continues with the next character. The replacement character is U+FFFD
for transcoders whose codec is one of the Unicode encodings, but is the ?
character for the Latin-1 encoding. If the error-handling mode is raise,
an exception with condition type &i/o-encoding is raised.
replace. The result is a
transcoder with the behaviour specified by its arguments.
make-transcoder, they return the codec,
eol-style, and handling-mode arguments, respectively.
textual-port? procedure returns #t if obj
is textual port, otherwise #f.
The binary-port? procedure returns #t if obj is binary port,
otherwise #f.transcoded-port procedure returns a new textual port
with the specified transcoder. Otherwise the new textual port's state is
largely the same as that of binary-port. If binary-port is an input
port, the new textual port will be an input port and will transcode the bytes
that have not yet been read from binary-port. If binary-port is an
output port, the new textual port will be an output port and will transcode
output characters into bytes that are written to the byte sink represented by
binary-port.
port-has-port-position? procedure returns #t if the
port supports the port-position operation, and #f otherwise.
The port-position procedure returns the index of the position at which the
next position would be read from or written to the port as an exact non-negative
integer object.
port-has-set-port-position!? procedure returns #t if the
port supports the set-port-position! operation, and #f otherwise.
The set-port-position! procedure raises an exception with condition type
&assertion if the port does not support the operation, and an exception
with condition type &i/o-invalid-position if pos is not in the range of
valid positions of port. Otherwise, it sets the current position of the
port to pos. If port is an output port,
set-port-position! first flushes port.
The optional argument whence must be one of the following symbols;
begin
current
end
begin even though user specified it
as current or end.
close-port procedure returns unspecified
values.
call-with-port
procedure calls proc with port as an argument. If proc
returns, port is closed automatically and the values returned by
proc are returned. If proc does not return, port is not
closed automatically, except perhaps when it is possible to prove that
port will never again be used for an input or output operation.
get-char raises
an get-char may successfully decode a character if bytes completing the
encoding are available after the end of file.
lookahead-u8 procedure (if
input-port is a binary port) or the lookahead-char procedure (if
input-port is a textual port) would return the end-of-file object, and
#f otherwise.
(file-options).
The buffer-mode argument, if supplied, must be one of the symbols that
name a buffer mode. The buffer-mode argument defaults to block.
If maybe-transcoder is a transcoder, it becomes the transcoder associated
with the returned port.
If maybe-transcoder is #f or absent, the port will be a binary port,
otherwise the port will be textual port.
open-bytevector-input-port procedure returns an input port whose
bytes are drawn from bytevector. If transcoder is specified, it
becomes the transcoder associated with the returned port.
If transcoder is #f or absent, the port will be a binary port,
otherwise the port will be textual port.
Optional arguments start and end restricts the range of
input bytevector. It is almost the same as following code but doesn't
allocate extra memory;
(open-bytevector-input-port (bytevector-copy bytevector start end))
(open-string-input-port (substring string start end))These procedures reuse the given arguments, thus if bytevector is modified after
open-bytevector-input-port has been called, it affects the result
of the port. So does open-string-input-port.
current-input-port sets the
port as a default port for input. Otherwise it returns a default input
port.Start will be a non-negative exact integer object, count will be a positive exact integer object, and bytevector will be a bytevector whose length is at least start + count. The read! procedure should obtain up to count bytes from the byte source, and should write those bytes into bytevector starting at index start. The read! procedure should return an exact integer object. This integer object should represent the number of bytes that it has read. To indicate an end of file, the read! procedure should write no bytes and return 0.
The get-position procedure (if supplied) should return an exact integer
object representing the current position of the input port. If not supplied, the
custom port will not support the port-position operation.
Pos will be a non-negative exact integer object. The set-position! procedure (if supplied) should set the position of the input port to pos. If not supplied, the custom port will not support the set-port-position! operation.
The close procedure (if supplied) should perform any actions that are necessary when the input port is closed.
The ready procedure (if supplied) should indicate the port data are ready or not.
Start will be a non-negative exact integer object, count will be a positive exact integer object, and string will be a string whose length is at least start + count. The read! procedure should obtain up to count characters from the character source, and should write those characters into string starting at index start. The read! procedure should return an exact integer object representing the number of characters that it has written. To indicate an end of file, the read! procedure should write no bytes and return 0.
The get-position procedure (if supplied) should return a single value.
The return value should represent the current position of the input port. If not
supplied, the custom port will not support the port-position operation.
The set-position! procedure (if supplied) should set the position of
the input port to pos if pos is the return value of a call to
get-position. If not supplied, the custom port will not support the
set-port-position! operation.
The close procedure (if supplied) should perform any actions that are necessary when the input port is closed.
The ready procedure (if supplied) should indicate the port characters are ready or not.
get-u8 returns the byte as an octet and
updates binary-input-port to point just past that byte. If no input byte
is seen before an end of file is reached, the end-of-file object is returned.
lookahead-u8 procedure is like get-u8, but it
does not update binary-input-port to point past the byte.get-bytevector-n procedure reads from binary-input-port,
blocking as necessary, until count bytes are available from
binary-input-port or until an end of file is reached. If count
bytes are available before an end of file, get-bytevector-n returns a
bytevector of size count.
If fewer bytes are available before an end of file, get-bytevector-n
returns a bytevector containing those bytes. In either case, the input port is
updated to point just past the bytes read. If an end of file is reached before
any bytes are available, get-bytevector-n returns the end-of-file object.
get-bytevector-n! procedure reads from binary-input-port,
blocking as necessary, until count bytes are available from
binary-input-port or until an end of file is reached. If count bytes
are available before an end of file, they are written into bytevector
starting at index start, and the result is count. If fewer bytes are
available before the next end of file, the available bytes are written into
bytevector starting at index start, and the result is a number object
representing the number of bytes actually read. In either case, the input port is
updated to point just past the bytes read. If an end of file is reached before
any bytes are available, get-bytevector-n! returns the end-of-file object.
get-bytevector-some returns a freshly
allocated bytevector containing the initial available bytes (at least one and
maximum 512 bytes), and it updates binary-input-port to point just past
these bytes. If no input bytes are seen before an end of file is reached, the
end-of-file object is returned.
get-bytevector-all returns a
bytevector containing all bytes up to the next end of file. Otherwise,
get-bytevector-all returns the end-of-file object.
These procedures can take optional argument reckless. If this is given,
these procedures can read bytes from textual port. This optional argument is for
socket programming. Users needs to make sure that the given port can be read as
textual port after reading port recklessly.
get-char
returns that character and updates the input port to point past the character.
If an end of file is reached before any character is read, get-char
returns the end-of-file object.
lookahead-char procedure is like get-char, but it
does not update textual-input-port to point past the character.
get-string-n procedure reads from textual-input-port, blocking
as necessary, until count characters are available, or until an end of
file is reached.
If count characters are available before end of file, get-string-n
returns a string consisting of those count characters. If fewer characters
are available before an end of file, but one or more characters can be read,
get-string-n returns a string containing those characters. In either case,
the input port is updated to point just past the characters read. If no characters
can be read before an end of file, the end-of-file object is returned.
get-string-n! procedure reads from textual-input-port in the
same manner as get-string-n. If count characters are available before
an end of file, they are written into string starting at index start,
and count is returned. If fewer characters are available before an end of
file, but one or more can be read, those characters are written into string
starting at index start and the number of characters actually read is
returned as an exact integer object. If no characters can be read before an end
of file, the end-of-file object is returned.
get-string-n and get-string-n!.
If characters are available before the end of file, a string containing all the
characters decoded from that data are returned. If no character precedes the end
of file, the end-of-file object is returned.
get-string-n and get-string-n!.
If a linefeed character is read, a string containing all of the text up to (but
not including) the linefeed character is returned, and the port is updated to
point just past the linefeed character. If an end of file is encountered before
any linefeed character is read, but some characters have been read and decoded
as characters, a string containing those characters is returned. If an end of
file is encountered before any characters are read, the end-of-file object is
returned.
get-datum procedure returns the next
datum that can be parsed from the given textual-input-port, updating
textual-input-port to point exactly past the end of the external
representation of the object.
If a character inconsistent with an external representation is encountered in
the input, an exception with condition types &lexical and &i/o-read
is raised. Also, if the end of file is encountered after the beginning of an
external representation, but the external representation is incomplete and
therefore cannot be parsed, an exception with condition types &lexical
and &i/o-read is raised.
flush-output-port procedure returns unspecified values.
If the optional argument is omitted then (current-output-port) will be
used.
open-file-output-port procedure returns an output port for the named
file.
The file-options argument, which may determine various aspects of the
returned port, defaults to the value of (file-options).
The buffer-mode argument, if supplied, must be one of the symbols that
name a buffer mode. The buffer-mode argument defaults to block.
If maybe-transcoder is a transcoder, it becomes the transcoder associated
with the port.
If maybe-transcoder is #f or absent, the port will be a binary port,
otherwise the port will be textual port.
open-bytevector-output-port procedure returns two values: an output
port and an extraction procedure. The output port accumulates the bytes written
to it for later extraction by the procedure.
If maybe-transcoder is a transcoder, it becomes the transcoder associated
with the port. If maybe-transcoder is #f or absent, the port will be a
binary port, otherwise the port will be textual port.
The extraction procedure takes no arguments. When called, it returns a bytevector
consisting of all the port's accumulated bytes (regardless of the port's current
position), removes the accumulated bytes from the port, and resets the port's
position.
call-with-bytevector-output-port procedure creates an output port that
accumulates the bytes written to it and calls proc with that output port as
an argument. Whenever proc returns, a bytevector consisting of all of the
port's accumulated bytes (regardless of the port's current position) is returned
and the port is closed.
The transcoder associated with the output port is determined as for a call to
open-bytevector-output-port.
call-with-string-output-port procedure creates a textual output port
that accumulates the characters written to it and calls proc with that
output port as an argument. Whenever proc returns, a string consisting of all of
the port's accumulated characters (regardless of the port's current position) is
returned and the port is closed.
make-custom-binary-input-port.
Start and count will be non-negative exact integer objects, and bytevector will be a bytevector whose length is at least start + count. The write! procedure should write up to count bytes from bytevector starting at index start to the byte sink. If count is 0, the write! procedure should have the effect of passing an end-of-file object to the byte sink. In any case, the write! procedure should return the number of bytes that it wrote, as an exact integer object.
make-custom-textual-input-port.
Start and count will be non-negative exact integer objects, and string will be a string whose length is at least start + count. The write! procedure should write up to count characters from string starting at index start to the character sink. If count is 0, the write! procedure should have the effect of passing an end-of-file object to the character sink. In any case, the write! procedure should return the number of characters that it wrote, as an exact integer object.
(bytevector-length bytevector) - start,
respectively. Bytevector must have a length of at least start + count.
The put-bytevector procedure writes the count bytes of the bytevector
bytevector starting at index start to the output port. The
put-bytevector procedure returns unspecified values.
(string-length string) - start. The put-string procedure
writes the count characters of string starting at index start to the
port. The put-string procedure returns unspecified values.
put-datum procedure
writes an external representation of datum to textual-output-port.
open-file-output-port. If the input/output port supports
port-position and/or set-port-position!, the same port position
is used for both input and output.
make-custom-binary-input-port and
make-custom-binary-output-port procedures.
Each of the remaining arguments may be #f; if any of those arguments is not #f,
it must be a procedure and should behave as specified in the description of
make-custom-binary-input-port.
make-custom-textual-input-port and
make-custom-textual-output-port procedures.
Each of the remaining arguments may be #f; if any of those arguments is not #f,
it must be a procedure and should behave as specified in the description of
make-custom-textual-input-port.
(rnrs io simple (6))library, which provides
a somewhat more convenient interface for performing textual I/O on ports.
(rnrs io posts (6)) library. I do not write the documentation of it, if
you want to import only this library, make sure which procedures are exported.
You can see it on R6RS.
open-input-file or
open-output-file.
open-input-file or
open-output-file.
get-char and lookahead-char.
If textual-input-port is omitted, it defaults to the value returned by
current-input-port.
current-input-port.
current-output-port.
write-char to write
#\linefeed to textual-output-port.
If textual-output-port is omitted, it defaults to the value returned by
current-output-port.
current-output-port.
write procedure operates in the same way
as put-datum.
If textual-output-port is omitted, it defaults to the value returned by
current-output-port.
file-exists? procedure returns #t if the named file exists at the time
the procedure is called, #f otherwise.
delete-file procedure deletes the named file if it exists and can be
deleted, and returns unspecified values. If the file does not exist or cannot be
deleted, an exception with condition type &i/o-filename is raised.
&implementation-restriction is raised if that sum or product is not a
fixnum.
&implementation-restriction is raised if
the mathematically correct result of this procedure is not a fixnum.
NOTE: R6RS says it raises &assertion if the result is not fixnum, however
Sagittarius raises &implementation-restriction for consistency with
fx+ and fx*.
(rnrs base (6))
section.
(let* ((s (+ fx1 fx2 fx3))
(s0 (mod0 s (expt 2 (fixnum-width))))
(s1 (div0 s (expt 2 (fixnum-width)))))
(values s0 s1))
(let* ((d (- fx1 fx2 fx3))
(d0 (mod0 d (expt 2 (fixnum-width))))
(d1 (div0 d (expt 2 (fixnum-width)))))
(values d0 d1))
(let* ((s (+ (* fx1 fx2) fx3))
(s0 (mod0 s (expt 2 (fixnum-width))))
(s1 (div0 s (expt 2 (fixnum-width)))))
(values s0 s1))
(fxior (fxand fx1 fx2)
(fxand (fxnot fx1) fx3))
(fxnot (fxbit-count (fxnot ei)))
(fxnot fx) if
it is negative, which is the fixnum result of the following computation:
(do ((result 0 (+ result 1))
(bits (if (fxnegative? fx)
(fxnot fx)
fx)
(fxarithmetic-shift-right bits 1)))
((fxzero? bits)
result))
(fixnum-width).
The fxbit-set? procedure returns #t if the fx2th bit is 1 in the
two's complement representation of fx1, and #f otherwise. This is the
fixnum result of the following computation:
(not
(fxzero?
(fxand fx1
(fxarithmetic-shift-left 1 fx2))))
(fixnum-width).
Fx3 must be 0 or 1. The fxcopy-bit procedure returns the result of
replacing the fx2th bit of fx1 by fx3, which is the result of
the following computation:
(let* ((mask (fxarithmetic-shift-left 1 fx2)))
(fxif mask
(fxarithmetic-shift-left fx3 fx2)
fx1))
(fixnum-width). Moreover, fx2 must be less than or equal to
fx3. The fxbit-field procedure returns the number represented by
the bits at the positions from fx2 (inclusive) to fx3 (exclusive),
which is the fixnum result of the following computation:
(let* ((mask (fxnot
(fxarithmetic-shift-left -1 fx3))))
(fxarithmetic-shift-right (fxand fx1 mask)
fx2))
(fixnum-width). Moreover, fx2 must be less than or equal to
fx3. The fxcopy-bit-field procedure returns the result of replacing
in fx1 the bits at positions from fx2 (inclusive) to fx3
(exclusive) by the corresponding bits in fx4, which is the fixnum result
of the following computation:
(let* ((to fx1)
(start fx2)
(end fx3)
(from fx4)
(mask1 (fxarithmetic-shift-left -1 start))
(mask2 (fxnot
(fxarithmetic-shift-left -1 end)))
(mask (fxand mask1 mask2)))
(fxif mask
(fxarithmetic-shift-left from start)
to))
(fixnum-width). If
(floor (* fx1 (expt 2 fx2)))is a fixnum, then that fixnum is returned. Otherwise an exception with condition type
&implementation-restriction is raised.
(fixnum-width).
The fxarithmetic-shift-left procedure behaves the same as
fxarithmetic-shift, and (fxarithmetic-shift-right fx1 fx2)
behaves the same as (fxarithmetic-shift fx1 (fx- fx2)).
(fixnum-width). Fx2 must be less than or equal to fx3.
Fx4 must be less than the difference between fx3 and fx2. The
fxrotate-bit-field procedure returns the result of cyclically permuting
in fx1 the bits at positions from fx2 (inclusive) to fx3
(exclusive) by fx4 bits towards the more significant bits, which is the
result of the following computation:
(let* ((n fx1)
(start fx2)
(end fx3)
(count fx4)
(width (fx- end start)))
(if (fxpositive? width)
(let* ((count (fxmod count width))
(field0
(fxbit-field n start end))
(field1
(fxarithmetic-shift-left
field0 count))
(field2
(fxarithmetic-shift-right
field0 (fx- width count)))
(field (fxior field1 field2)))
(fxcopy-bit-field n start end field))
n))
(fixnum-width). Moreover, fx2 must be less than or equal to fx3.
The fxreverse-bit-field procedure returns the fixnum obtained from
fx1 by reversing the order of the bits at positions from fx2
(inclusive) to fx3 (exclusive).
(rnrs arithmetic flonums (6))library.
This section uses fl, fl1, fl2, etc., as parameter names for
arguments that must be flonums, and ifl as a name for arguments that must
be integer-valued flonums, i.e., flonums for which the integer-valued?
predicate returns true.
flinteger? procedure tests whether the number
object is an integer, flzero? tests whether it is fl=? to zero,
flpositive? tests whether it is greater than zero, flnegative?
tests whether it is less than zero, flodd? tests whether it is
odd, fleven? tests whether it is even, flfinite? tests whether
it is not an infinity and not a NaN, flinfinite? tests whether it is
an infinity, and flnan? tests whether it is a NaN.
(rnrs base (6))
. For zero divisors, these
procedures may return a NaN or some unspecified flonum.
flfloor returns the largest
integral flonum not larger than fl. The flceiling procedure returns
the smallest integral flonum not smaller than fl. The fltruncate
procedure returns the integral flonum closest to fl whose absolute value
is not larger than the absolute value of fl. The flround procedure
returns the closest integral flonum to fl, rounding to even when fl
represents a number halfway between two integers.
Although infinities and NaNs are not integer objects, these procedures return an
infinity when given an infinity as an argument, and a NaN when given a NaN.
flexp
procedure computes the base-e exponential of fl. The fllog procedure
with a single argument computes the natural logarithm of fl1 (not the base
ten logarithm); (fllog fl1 fl2) computes the base-fl2
logarithm of fl1. The flasin, flacos, and flatan
procedures compute arcsine, arccosine, and arctangent, respectively.
(flatan fl1 fl2) computes the arc tangent of fl1/fl2.
flsqrt
returns 0.0; for other negative arguments, the result unspecified flonum.
flexpt procedure returns fl1
raised to the power fl2. If fl1 is negative and fl2 is not an
integer object, the result is a NaN. If fl1 is zero, then the result is zero.
+ &implementation-restriction (see "Conditions") + &no-infinities + &no-nans
(rnrs arithmetic bitwise (6))library.
The exact bitwise arithmetic provides generic operations on exact integer
objects. This section uses ei, ei1, ei2, etc., as parameter
names that must be exact integer objects.
(bitwise-ior (bitwise-and ei1 ei2)
(bitwise-and (bitwise-not ei1) ei3))
(bitwise-not (bitwise-bit-count (bitwise-not ei)))
(bitwise-not ei) if it is negative, which is the exact integer
object that is the result of the following computation:
(do ((result 0 (+ result 1))
(bits (if (negative? ei)
(bitwise-not ei)
ei)
(bitwise-arithmetic-shift bits -1)))
((zero? bits)
result))
bitwise-bit-set?
procedure returns #t if the ei2th bit is 1 in the two's complement
representation of ei1, and #f otherwise. This is the result of the
following computation:
(not (zero?
(bitwise-and
(bitwise-arithmetic-shift-left 1 ei2)
ei1)))
bitwise-copy-bit procedure returns the result of replacing the
ei2th bit of ei1 by the ei2th bit of ei3, which is the
result of the following computation:
(let* ((mask (bitwise-arithmetic-shift-left 1 ei2)))
(bitwise-if mask
(bitwise-arithmetic-shift-left ei3 ei2)
ei1))
bitwise-bit-field procedure returns
he number represented by the bits at the positions from ei2 (inclusive) to
ei3 (exclusive), which is the result of the following computation:
(let ((mask
(bitwise-not
(bitwise-arithmetic-shift-left -1 ei3))))
(bitwise-arithmetic-shift-right
(bitwise-and ei1 mask)
ei2))
bitwise-copy-bit-field procedure
returns the result of replacing in ei1 the bits at positions from
var{ei2} (inclusive) to ei3 (exclusive) by the corresponding bits in
ei4, which is the fixnum result of the following computation:
(let* ((to ei1)
(start ei2)
(end ei3)
(from ei4)
(mask1
(bitwise-arithmetic-shift-left -1 start))
(mask2
(bitwise-not
(bitwise-arithmetic-shift-left -1 end)))
(mask (bitwise-and mask1 mask2)))
(bitwise-if mask
(bitwise-arithmetic-shift-left from
start)
to))
(floor (* ei1 (expt 2 ei2)))ei2 must be a fixnum. This is implementation restriction.
bitwise-arithmetic-shift-left procedure returns the same result as
bitwise-arithmetic-shift, and
(bitwise-arithmetic-shift-right ei1 ei2)returns the same result as
(bitwise-arithmetic-shift ei1 (- ei2)). ei2 must be a fixnum. This is implementation restriction.
bitwise-rotate-bit-field procedure returns the result of cyclically
permuting in ei1 the bits at positions from ei2 (inclusive) to
ei3 (exclusive) by ei4 bits towards the more significant bits,
which is the result of the following computation:
(let* ((n ei1)
(start ei2)
(end ei3)
(count ei4)
(width (- end start)))
(if (positive? width)
(let* ((count (mod count width))
(field0
(bitwise-bit-field n start end))
(field1 (bitwise-arithmetic-shift-left
field0 count))
(field2 (bitwise-arithmetic-shift-right
field0
(- width count)))
(field (bitwise-ior field1 field2)))
(bitwise-copy-bit-field n start end field))
n))
ei4 must be a fixnum. This is implementation restriction.
bitwise-reverse-bit-field procedure
returns the result obtained from ei1 by reversing the order of the bits at
positions from ei2 (inclusive) to ei3 (exclusive).
(rnrs syntax-case (6))library provides support for
writing low-level macros in a high-level style, with automatic syntax checking,
input destructuring, output restructuring, maintenance of lexical scoping and
referential transparency (hygiene), and support for controlled identifier capture.
(pattern output-expression)
(pattern fender output-expression)Fender and output-expression must be expressions. Pattern is the same as
syntax-rules. See
(rnrs base (6)) section.
A syntax-case expression first evaluates expression. It then attempts to
match the pattern from the first clause against the resulting value,
which is unwrapped as necessary to perform the match. If the pattern
matches the value and no fender is present, output-expression is
evaluated and its value returned as the value of the syntax-case expression.
If the pattern does not match the value, syntax-case tries the second
clause, then the third, and so on. It is a syntax violation if the value
does not match any of the patterns.
If the optional fender is present, it serves as an additional constraint on
acceptance of a clause. If the pattern of a given clause matches the
input value, the corresponding fender is evaluated. If fender evaluates
to a true value, the clause is accepted; otherwise, the clause is
rejected as if the pattern had failed to match the value. Fenders are
logically a part of the matching process, i.e., they specify additional matching
constraints beyond the basic structure of the input.
Pattern variables contained within a clause's pattern are bound to the
corresponding pieces of the input value within the clause's fender (if present)
and output-expression. Pattern variables can be referenced only within syntax
expressions (see below). Pattern variables occupy the same name space as program
variables and keywords.
If the syntax-case form is in tail context, the output-expressions
are also in tail position.
(subtemplate ...)
(subtemplate ... . template)
#(subtemplate ...)A subtemplate is a template followed by zero or more ellipses. The value of a
syntax form is a copy of template in which the
pattern variables appearing within the template are replaced with the input
subforms to which they are bound. Pattern data and identifiers that are not
pattern variables or ellipses are copied directly into the output. A
subtemplate followed by an ellipsis expands into zero or more occurrences
of the subtemplate. Pattern variables that occur in subpatterns followed
by one or more ellipses may occur only in subtemplates that are followed by
(at least) as many ellipses. These pattern variables are replaced in the output
by the input subforms to which they are bound, distributed as specified. If a
pattern variable is followed by more ellipses in the subtemplate than in
the associated subpattern, the input form is replicated as necessary. The
subtemplate must contain at least one pattern variable from a subpattern
followed by an ellipsis, and for at least one such pattern variable, the
subtemplate must be followed by exactly as many ellipses as the subpattern
in which the pattern variable appears.
bound-identifier=? returns #t if given arguments are exactly the same object.
The bound-identifier=? procedure can be used for detecting duplicate
identifiers in a binding construct or for other preprocessing of a binding
construct that requires detecting instances of the bound identifiers.
free-identifier=?
procedure returns #t if given arguments are indicating the same bindings.
datum->syntax procedure returns a syntax-object representation of
datum that contains the same contextual information as template-id,
with the effect that the syntax object behaves as if it were introduced into the
code when template-id was introduced.
The datum->syntax procedure allows a transformer to "bend" lexical scoping
rules by creating implicit identifiers that behave as if they were present in the
input form, thus permitting the definition of macros that introduce visible
bindings for or references to identifiers that do not appear explicitly in the
input form. For example, the following defines a loop expression that uses
this controlled form of identifier capture to bind the variable break to an escape
procedure within the loop body.
(define-syntax loop
(lambda (x)
(syntax-case x ()
[(k e ...)
(with-syntax
([break (datum->syntax (syntax k) 'break)])
(syntax
(call-with-current-continuation
(lambda (break)
(let f () e ... (f))))))])))
(let ((n 3) (ls '()))
(loop
(if (= n 0) (break ls))
(set! ls (cons 'a ls))
(set! n (- n 1))))
=>
(a a a)
gensym in (sagittarius) library.
with-syntax form is used to bind pattern variables, just
as syntax-case pattern. The
value of each expression is computed and destructured according to the
corresponding pattern, and pattern variables within the pattern are
bound as with syntax-case to the corresponding portions of the value
within body.
quasisyntax form is similar to syntax, but it
allows parts of the quoted text to be evaluated, in a manner similar to the
operation of quasiquote.
Within a quasisyntax template, subforms of unsyntax and
unsyntax-splicing forms are evaluated, and everything else is treated
as ordinary template material, as with syntax. The value of each
unsyntax subform is inserted into the output in place of the unsyntax
form, while the value of each unsyntax-splicing subform is spliced into
the surrounding list or vector structure. Uses of unsyntax and
unsyntax-splicing are valid only within quasisyntax expressions.
A quasisyntax expression may be nested, with each quasisyntax
introducing a new level of syntax quotation and each unsyntax or
unsyntax-splicing taking away a level of quotation. An expression nested
within n quasisyntax expressions must be within n unsyntax or
unsyntax-splicing expressions to be evaluated.
syntax-violation procedure raises an exception, reporting a syntax
violation. Who should describe the macro transformer that detected the
exception. The message argument should describe the violation. Form
should be the erroneous source syntax object or a datum value representing a form.
The optional subform argument should be a syntax object or datum value
representing a form that more precisely locates the violation.
(rnrs hashtables (6))library provides a set of operations on
hashtables. A hashtable is a data structure that associates keys with
values. Any object can be used as a key, provided a hash function and a
suitable equivalence function is available. A hash function is a
procedure that maps keys to exact integer objects. It is the programmer's
responsibility to ensure that the hash function is compatible with the
equivalence function, which is a procedure that accepts two keys and returns
true if they are equivalent and #f otherwise. Standard hashtables for arbitrary
objects based on the eq? and eqv? predicates are provided. Also,
hash functions for arbitrary objects, strings, and symbols are provided.
This section uses the hashtable parameter name for arguments that must be
hashtables, and the key parameter name for arguments that must be
hashtable keys.
eq?
(make-eq-hashtable) or eqv? (make-eqv-hashtable).
If optional argument k is given, it must be exact non-negative integer or
#f. If it's #f, then the procedure picks up default initial
capacity, otherwise the initial capacity of the hashtable is set to
approximately k elements.
If optional argument weakness is given, then it must be one of the
symbols key, value or both, or #f. If the value is
one of the symbols, then the procedure creates weak hashtable of given symbol's
weakness. If the symbol is key, then entries whose keys are refered only
from this hashtable might be removed when garbage collection is
occurred. value is for entry values. both is for both.
make-hashtable procedure returns a newly allocated mutable hashtable
using hash-function as the hash function and equiv as the
equivalence function used to compare keys.
If optional argument k and weakness are the same as
make-eq-hashtable and make-eqv-hashtable.
hashtable-ref and hashtable-contains? do
not make any difference fot the performance.
hashtable-update! procedure applies proc to the value in
hashtable associated with key, or to default if
hashtable does not contain an association for key. The
hashtable is then changed to associate key with the value returned
by proc.
}
equal? and symbols.
string=? and string-ci=?.
If the optional argument start and end is given, then the given
string will be substringed with start and end.
If the optional argument bound is given, it must be exact integer and hash
function will also use the given value.
(rnrs enums (6))library for dealing with
enumerated values and sets of enumerated values. Enumerated values are represented
by ordinary symbols, while finite sets of enumerated values form a separate type,
known as the enumeration sets. The enumeration sets are further partitioned
into sets that share the same universe and enumeration type. These
universes and enumeration types are created by the make-enumeration
procedure. Each call to that procedure creates a new enumeration type.
make-enumeration procedure creates a new enumeration type whose
universe consists of those symbols (in canonical order of their first appearance
in the list) and returns that universe as an enumeration set whose universe is
itself and whose enumeration type is the newly created enumeration type.
enum-set-member? procedure returns #t if its first
argument is an element of its second argument, #f otherwise.
The enum-set-subset? procedure returns #t if the universe of
enum-set1 is a subset of the universe of enum-set2 (considered as
sets of symbols) and every element of enum-set1 is a member of
enum-set2. It returns #f otherwise.
The enum-set=? procedure returns #t if enum-set1 is a subset of
enum-set2 and vice versa, as determined by the enum-set-subset?
procedure. This implies that the universes of the two sets are equal as sets of
symbols, but does not imply that they are equal as enumeration types. Otherwise,
#f is returned.
enum-set-union procedure returns the union of enum-set1 and
enum-set2.
The enum-set-intersection procedure returns the intersection of
enum-set1 and enum-set2.
The enum-set-difference procedure returns the difference of enum-set1
and enum-set2.
define-enumeration form defines an enumeration type and
provides two macros for constructing its members and sets of its members.
A define-enumeration form is a definition and can appear anywhere any
other definition can appear.
Type-name is an identifier that is bound as a syntactic keyword;
symbol ... are the symbols that comprise the universe of the enumeration
(in order).
(type-name symbol) checks at macro-expansion time whether the
name of symbol is in the universe associated with type-name. If it is,
(type-name symbol) is equivalent to symbol. It is a syntax
violation if it is not.
Constructor-syntax is an identifier that is bound to a macro that, given any
finite sequence of the symbols in the universe, possibly with duplicates, expands
into an expression that evaluates to the enumeration set of those symbols.
(constructor-syntax symbol ...) checks at macro-expansion
time whether every symbol ... is in the universe associated with
type-name. It is a syntax violation if one or more is not. Otherwise
(constructor-syntax symbol ...)is equivalent to
((enum-set-constructor (constructor-syntax)) '(symbol ...)).
(rnrs eval (6)) library allows a program to create Scheme
expressions as data at run time and evaluate them.
environment procedure. However on Sagittarius, environment can be
anything. This behaviour might be fixed in future.
environment procedure returns an environment corresponding to import-spec.
set-car! and set-cdr!.string-set! and string-fill!.string-set! procedure stores char in element k of string
and returns unspecified values.
&assertion to be raised.
exact->inexact.inexact and exact procedures.delay construct is used together with the procedure
force to implement lazy evaluation or call by need.
(delay expression) returns an object called a promise which
at some point in the future may be asked (by the force procedure) to
evaluate expression, and deliver the resulting value. The effect of expression
returning multiple values is unspecified.
force procedure forces the value of promise. If no value has
been computed for the promise, then a value is computed and returned. The value
of the promise is cached (or "memoized") so that if it is forced a second time,
the previously computed value is returned.
eval.
export export-spec ...)import import-set ...)begin command-or-definition ...)include filenames ...)include-ci filenames ...)include-library-declarations filenames ...)cond-expand cond-expand-clause ...)export and import are the same as R6RS. And on R7RS renaming
export syntax is different from R6RS, however on Sagittarius both can be
accepted.
begin starts the library contents. However it can appear more than once.
include and include-ci includes the files which are specified
filenames. filenames must be string. This resolves file path from
current loading file. If the library file is /usr/local/lib/lib1.scm, then
search path will be /usr/local/lib. It can also take absolute path.
include-ci reads the file case insensitive.
cond-exnpand is the same as builtin syntax cond-expand. For more
detail, see Builtin Syntax.
* + - ... / < <= = => > >= abs and append apply assoc assq assv begin binary-port? boolean=? boolean? bytevector-copy bytevector-length bytevector-u8-ref bytevector-u8-set! bytevector? caar cadr call-with-current-continuation call-with-port call-with-values call/cc car case cdar cddr cdr ceiling char->integer char<=? char<? char=? char>=? char>? char? close-input-port close-output-port close-port complex? cond cons current-error-port current-input-port current-output-port define define-record-type define-syntax denominator do dynamic-wind else eof-object eof-object? eq? eqv? error even? exact exact-integer-sqrt exact? expt floor flush-output-port for-each gcd guard if inexact inexact? input-port? integer->char integer? lambda lcm length let let* let*-values let-values letrec letrec* list list->string list->vector list-ref list-tail list? make-bytevector make-string make-vector map max member memq memv min modulo negative? newline not null? number->string number? numerator odd? or output-port? pair? peek-char port? positive? procedure? quasiquote quote quotient raise raise-continuable rational? rationalize read-char real? remainder reverse round set! set-car! set-cdr! string string->list string->number string->symbol string->utf8 string-append string-copy string-for-each string-length string-ref string-fill! string-set! string<=? string<? string=? string>=? string>? string? substring symbol->string symbol=? symbol? syntax-rules textual-port? truncate unless unquote unquote-splicing utf8->string values vector vector->list vector-fill! vector-for-each vector-length vector-map vector-ref vector-set! vector? when with-exception-handler write-char zero?This is defined in (sagittarius);
cond-expand
(converter init) if converter
is given, otherwise init.
If the parameter object is applied without an argument, then it returns
the value associated with the parameter object.
If the parameter object is applied with an argument, then it changes the
associated value with the given value which may converted by converter
if the parameter object is created with converter.
parameterize expression is used to change the
values returned by specified parameter objects during the evaluation of
body.include-ci reads
files case insensitively.
lambda
expression are matched to the arguments in a procedure call.
/ returns two integers; the other procedures
return an integer. All the procedures compute a quotient nq and
remainder nr such that n1 = n2*nq + nr.
for each of the division operators, there are three procedures defined as
follows;
(<operator>/ n1 n2)=> nq nr
(<operator>-quotient n1 n2)=> nq
(<operator>-remainder n1 n2)=> nr
nq:nr = n1 - n2*nq. Each set of
operations uses a different choice of nq:
floor: nq = [n1/n2]
truncate: nq = truncate(n1/n2)
Examples;
(floor/ 5 2)=> 2 1
(floor/ -5 2)=> -3 1
(floor/ 5 -2)=> -3 -1
(floor/ -5 -2)=> 2 -1
(truncate/ 5 2)=> 2 1
(truncate/ -5 2)=> -2 -1
(truncate/ 5 -2)=> -2 1
(truncate/ -5 -2)=> 2 -1
(truncate/ -5.0 -2)=> 2.0 -1.0
&syntax with syntax-violation.
The macro is defined like this;
(define-syntax syntax-error
(syntax-rules ()
((_ msg args ...)
(syntax-violation 'syntax-error msg (quote args ...)))))
consition?.
irritants-condition?. Otherwise #f.
message-condition?. Otherwise #f.
i/o-read-error?.port-ready?.
\n, \r
and \r\n are considered end of line.
cond-expand
treas as true.
(rnrs base) is that this procedure
inspect record fields as well. For example:
(import (rnrs))
(define-record-type (<pare> kons pare?)
(fields (mutable a kar set-kar!)
(mutable d kdr set-kdr!)))
(let ((a (kons 'a 'b))
(b (kons 'a 'b)))
(equal? a b))
=>
#f
(import (scheme base))
(define-record-type (<pare> kons pare?)
(fields (mutable a kar set-kar!)
(mutable d kdr set-kdr!)))
(let ((a (kons 'a 'b))
(b (kons 'a 'b)))
(equal? a b))
=>
#t
(rnrs base) and these macros is
that these macro create scope. Thus the following is unbound variable error:
(import (scheme base)) (let-syntax () (define foo 'foo)) foo=> &undefined
case-lambda syntax.
Exported macro is the same as R6RS;
case-lambda
char-alphabetic? char-ci<=? char-ci<? char-ci=? char-ci>=? char-ci>? char-downcase char-foldcase char-lower-case? char-numeric? char-upcase char-upper-case? char-whitespace? string-ci<=? string-ci<? string-ci=? string-ci>=? string-ci>? string-downcase string-foldcase string-upcase
(digit-value #\1)=> 1
(digit-value #\x0664)=> 4
(digit-value #\x0EA6)=> #f
(digit-value #\xbc)=> 1/4
(digit-value #\xbf0)=> 10
angle imag-part magnitude make-polar make-rectangular real-part
caaaar caaadr caaar caadar caaddr caadr cadaar cadadr cadar caddar cadddr caddr cdaaar cdaadr cdaar cdadar cdaddr cdadr cddaar cddadr cddar cdddar cddddr cdddr
environment eval
call-with-input-file call-with-output-file delete-file file-exists? open-input-file open-output-file with-input-from-file with-output-to-file
acos asin atan cos exp finite? infinite? log nan? sin sqrt tan
delay force make-promise promise?
(delay-force expression) is conceptually
similar to (delay (force expression)), with the difference that
forcing the result of delay-force will in effect result in a tail call
to (force expression), while forcing the result of
(delay (force expression)) might not.
command-line exit
read/ss.interaction-environment procedure.display
write/ss and write, respectively.
transcript-on and transcript-off are
not present. Note that the exact and inexact procedures
appear under their R5RS names inexact->exact and
exact->inexact respectively. However, if an implementation does
not provide a particular library such as the complex library, the
corresponding identifiers will not appear in this library either. This
library exports procedures for writing Scheme objects.
(srfi :1).
(srfi :133).
(srfi :132).
(srfi :113).
(srfi :14).
(srfi :125).
(srfi :116).
(srfi :101) with the following exceptions:
make-list is renamed to make-rlist.
random-access-list->linear-access-list is renamed to rlist->list.
linear-access-list->random-access-list is renamed to list->rlist.
All other procedures are prefixed with r. For example, pair?
exported from (srfi :101) is rpair?.
(srfi :134).
(srfi :135).
(srfi :158).
(srfi :127).
(srfi :41).
(srfi :111).
(srfi :117).
(srfi :124).
(srfi :128).
(srfi :141).
(srfi :143).
(srfi :144).
(srfi :146).
(srfi :146 hash).
(srfi :151).
(srfi :159).
(srfi :160 base).
(srfi :160 @). Where @ is one of
u8 s8 u16 s16 u32 s32 u64 s64 f32 f64 c64 c128
(rnrs bytevectors).
NOTE: The exporting names may conflicts with the ones exported from R7RS
libraries (e.g. bytevector-copy! from (scheme base)).
1 is instance of <integer> class.
However CLOS has huge features and I don't have intension to implement all of
it.
This section does not describe CLOS itself.
slots ::= (slot ...) slot ::= (slot-name specifiers*) specifiers ::=Defines a new class. Slot specifiers::init-keywordkeyword |:init-valuevalue |:init-formform |:readerreader-function |:writerwriter-function
:init-keyword
make procedure. Following code describes how to use:
(make <a-class> :slot-a 'slot-a-value)
<a-class> has a slot which slot definition contains the keyword
:init-keyword with the keyword :slot-a. The code initialises
an instance of the slot with given value slot-a-value.
:init-value
:init-form
:init-keyword but this keyword takes expression which
will be evaluated at initialiation time.
:reader
slot-ref
procedure.
:writer
slot-set! procedure.
:metaclass.
NOTE: Current implementation does not support :allocation keyword
by default. If you need it, see
(sagittarius mop allocation).
specifiers ::= (spec ... rest) spec ::= (argument-name class) | (argument-name) rest ::= '() | symbolAdds defined method to name generic. If the generic does not exist, this will create a new generic function implicitly.
equal? is called.
Defines how user defined class should be compared.
compute-getter-and-setter. This method should only
be used if users absolutely need to use accessor to access the target slots.
define however the define-constant binds
variable as a constant value and the compiler try to fold it if it is
constant value i.e. literal string, literal vector, literal number and so.
If the defined variable is being overwritten, the VM shows a warning
message on the standard error. If overwriten is forbidden by
#!no-overwite or other directives, then compiler raises an error.
lambda.
Expression must be an expression.
receive binds values which are generated by expressions to
formals.
The expressions in body are evaluated sequentially in the extended
environment. The results of the last expression in the body are the values of
the receive-expression.
cond-expand resolves
platform dependencies such as C's #ifdef preprocessor.
clauses must be one of these forms:
library library-name) body ...)and feature-identifier ...) body ...)or feature-identifier ...) body ...)not feature-identifier)library form searches the given library-name and if it is found,
then compiles body.
and, or and not are the same as usual syntax.
Users can check possible feature-identifiers via cond-features
procedure.
datum->syntax, it doesn't require template identifier.free-identifier=?. If the given
arguments are list or vector, then the procedure checks its elements.er-macro-transformer returns explicit renaming macro transformer, so
you can write both hygine and non-hygine macro with it. For example:
(define-syntax loop
(er-macro-transformer
(lambda (form rename compare)
(let ((body (cdr form)))
`(,(rename 'call/cc)
(,(rename 'lambda) (break)
(,(rename 'let) ,(rename 'f) () ,@body (,(rename 'f)))))))))
(let ((n 3) (ls '()))
(loop
(if (= n 0) (break ls))
(set! ls (cons 'a ls))
(set! n (- n 1))))
=>
(a a a)
datum->syntax description. The basic of er-macro-transformer is
the opposite way of the syntax-case. The syntax-case always makes
macro hygine, however the er-macro-transformer can make macro hygine.
Moreover, if you do not use rename, it always makes it non-hygine.
+, *, - and /. The difference is
these procedures converts given arguments inexact number.x ^ -1 mod mx ^ e mod m&i/o condition.
file-stat-ctime procedure returns last change time of filename.
The file-stat-mtime returns last modified time of filename.
The file-stat-atime returns last accesse time of filename.
&i/o.
If new-filename exists, it overwrite the existing file.
&i/o.
current-directory sets
current working directory to path and returns unspecified value.
make-eq-hashtable and
make-eqv-hashtable. It uses equal? or string=? as
comparing procedure, respectively.hashtable-keys.hashtable-keys and hashtable-values
are implemented with these procedures.
eq, eqv, equal, string and
general.
key, value and both. endianness macro.
Write v to out as unsigned/signed 16/32 bit integer.endianness macro.
Read a number from in as unsigned/signed 16/32.put-* and get-* have only 16 and 32 bit integers.
This is because benchmark told us there's not much difference between C and
Scheme implementation. We may add 64 bit integers and floting number
versions in future if there's enough demand.
read/ss reads a datum from given port.
The write/ss writes obj to given port.
These are the same as read and write procedure, but it can handle
circular list.
'~', and ends with some specific
characters. A format directive takes the corresponding arg and formats it. The
rest of string is copied to the output as is.
(format #f "the answer is ~a" 48)=> the anser is 48
'@' and colon ':'. One or both of them may modify the
behaviour of the format directive. Those flags must be placed immediately
before the directive character.
The following complete list of the supported directives. Either upper case or
lower case character can be used for the format directive; usually they have no
distinction, except noted.
display. If an
integer mincol is given, it specifies the minimum number of characters to
be output; if the formatted result is shorter than mincol, a whitespace is
padded to the right (i.e. the result is left justified).
The colinc, minpad and padchar parameters control, if given,
further padding. A character padchar replaces the padding character for the
whitespace. If an integer minpad is given and greater than 0, at least
minpad padding character is used, regardless of the resulting width. If an
integer colinc is given, the padding character is added (after minpad) in
chunk of colinc characters, until the entire width exceeds mincol.
If atmark-flag '@' is given, the format result is right
justified, i.e. padding is added to the left.
The maxcol parameter, if given, limits the maximum number of characters to
be written. If the length of formatted string exceeds maxcol, only
maxcol characters are written. If colon-flag is given as well and the
length of formatted string exceeds maxcol, maxcol - 4 characters
are written and a string " ..." is attached after it.
(format #f "|~a|" "oops")=> |oops|
(format #f "|~10a|" "oops")=> |oops |
(format #f "|~10@a|" "oops")=> | oops|
(format #f "|~10,,,'*@a|" "oops")=> |******oops|
(format #f "|~,,,,10a|" '(abc def ghi jkl))=> |abc def gh|
(format #f "|~,,,,10:a|" '(abc def ghi jkl))=> |abc de ...|
write. The
semantics of parameters and flags are the same as ~A directive.
(format #f "|~s|" "oops")=> |"oops"|
(format #f "|~10s|" "oops")=> |"oops" |
(format #f "|~10@s|" "oops")=> | "oops"|
(format #f "|~10,,,'*@s|" "oops")=> |****"oops"|
(format #f "|~d|" 12345)=> |12345|
(format #f "|~10d|" 12345)=> | 12345|
(format #f "|~10,'0d|" 12345)=> |0000012345|
'+' is printed for the positive
argument.
If colon-flag is given, every intervalth digit of the result is grouped
and commachar is inserted between them. The default of commachar is
',', and the default of interval is 3.
(format #f "|~:d|" 12345)=> |12,345|
(format #f "|~,,'_,4:d|" -12345678)=> |-1234_5678|
'X' is used, upper case alphabets are used for the digits larger than 10.
If 'x' is used, lower case alphabets are used. The semantics of
parameters and flags are the same as the ~D directive.
(format #f "~8,'0x" 259847592)=> 0f7cf5a8
(format #f "~8,'0X" 259847592)=> 0F7CF5A8
;; Assume read! is provided. (define user-port (make-custom-binary-input-port "my-port" read! #f #f)) (port-ready user-port)=> #t
(buffer-mode block) or (buffer-mode line) uses the buffered
port. This is useful when actual I/O is more expensive than memory access.
The buffer-mode must be a symbol the macro buffer-mode can
return. If the buffer-mode is none, then the procedure does not
convert the given port.
If the keyword argument buffer is specified, it must be
a bytevector, then the converted buffered port uses specified bytevector
as its internal buffer. If the bytevector size is zero or literal bytevector
then &assertion is raised.
ignore, raise or
replace depending on a transcoder which uses this custom codec.
Check-bom? is boolean, if getc is being called first time, it is #t,
otherwise #f. Userdata is user defined data which is given when the codec
is created.
The basic process of getc is reading binary data from input-port and
converting the data to UCS4. Returning UCS4 must be integer and does not have to
be 4 byte.
Putc must take 4 arguments, output-port, char,
error-handling-mode and userdata. Output-port is binary output
port. Char is character object which needs to be converted from UCS4.
Error-handling-mode is symbol can be ignore, raise or
replace depending on a transcoder which uses this custom codec.
Userdata is user defined data which is given when the codec is created.
The basic process of putc is converting given UCS4 charactner to target
encoding data and putting it to output-port as binary data.
For sample implementation, see sitelib/encoding directory. You can find some
custom codecs.
string<?, string<=?,
string>? and string>=?.
These can also be implemented as follows:
(define (symbol<? . syms) (apply string<? (map symbol->string syms)))However, this build-in version won't converts given symbols to strings.
':'. It has almost the
same feature as symbol, however it can not be bounded with any values. The
keyword objects are self quoting so users don't have to put ' explicitly.
The keyword notation is *NOT* available on R6RS or R7RS reader mode. Thus
#!r6rs or #!r7rs directive and -r6 or -r7
command line option disable it.
&error when keyword is not found in
list.
If fallback is given and the procedure could not find the keyword
from the list, the fallback will be return. Otherwise it raises
&error.
(get-keyword :key '(a b c :key d))=> d
(get-keyword :key '(a b c d e))=> &error
(get-keyword :key '(a b c d e) 'fallback)=> &error
(get-keyword :key '(a b c d e f) 'fallback)=> fallback
weak-vector-ref raise an &assertion if k is
negative, or greater than or equal to the size of wvec. However, if an
optional argument fallback is given, it is returned for such case.
If the element has been garbage collected, this procedure returns fallback
if it is given, #f otherwise.
&assertion if k is negative or greater than or equal to
the size of wvec.
eq? and eqv?,
respectively.
The keyword argument init-size specifies the initial size of the
weak hashtable.
The kwyword argument weakness specifies the place where the weak pointer
is. This must be one of the key, value and both. If the
key is specified, then weak hashtable's weak pointer will be the key
so is value. If the both is specified, then it will be both.
The keyword argument default specifies the default value when the entry
is garbage collected. If this is not spceified, then undefined value will be
used.
(integer->bytevector #x12345678 5)=> #vu8(#x00 #x12 #x34 #x56 #x78)
(integer->bytevector #x12345678 3)=> #vu8(#x34 #x56 #x78)
(apply bytevector-append list-of-bytevectors)
(cons (cons obj1 obj2) obj3). Useful to
put an entry at the head of an associative list.
(vector-copy '#(0 1 2 3 4) 1 4)=> #(1 2 3)
(vector-copy '#(0 1 2 3 4) 4 6 #f)=> #(4 #f)
(vector-copy '#() 0 2 #t)=> #(#t #t)
(vector-append '#(1 2) '#(a b) '#(5))=> #(1 2 a b 5)
(apply vector-append list-of-vectors)
index
#f.
This is the default behaviour.
before
#f if
item is not found.
after
#f if
item is not found.
before*
(values #f #f).
after*
(values #f #f).
both
(values #f #f).
(apply string-append list-of-strings)
"abc")string->istring#t, then given path is
appended to the current loading path list, otherwise prepend to the list.
#t, then given suffix is
appended to the current suffix list, otherwise prepend to the list.
The suffix should contain . as well.
uname(2).
On Windows environment, this is the result of couple of Win32 API calls
and formatted to look like the result of uname(2).
get-process-times returns value of _SC_CLK_TCK, and
get-thread-times returns 1000000 (on OSX), 1000000000 (on other POSIX
environments which have pthread_getcpuclockid), or _SC_CLK_TCK
(on other POSIX environments which don't have pthread_getcpuclockid). So
users must not assume the value is one of them and calculate CPU second with
assumed value.
taskset(1).
This procedure returns static value initialised during initialisation of
Sagittarius process. Thus, if the process is restricted after its
initialisation by taskset(1), for example the environment has 4 CPUs
but restricted to 1, then this process, however, returns 4.
time macro(define-macro name (lambda formals body ...))
let-optionals* where you have only one
optional argument. Given the optional argument list restargs, this macro
returns the value of optional argument if one is given, or the result of
default otherwise.
If latter form is used, test must be procedure which takes one argument
and it will be called to test the given argument. If the test failed, it raises
&error condition.
Default is not evaluated unless restargs is an empty list.
(symbol expr)If the restrag contains keyword which has the same name as symbol, binds symbol to the corresponding value. If such a keyword doesn't appear in restarg, binds symbol to the result of expr.
(symbol keyword expr)If the restarg contains keyword keyword, binds symbol to the corresponding value. If such a keyword doesn't appear in restarg, binds symbol to the result of expr. The default value expr is only evaluated when the keyword is not given to the restarg. If you use the first form,
let-keyword raises &error condition
when restarg contains a keyword argument that is not listed in
var-specs. When you want to allow keyword arguments other than listed in
var-specs, use the second form.
In the second form, restvar must be either a symbol or #f. If it is a
symbol, it is bound to a list of keyword arguments that are not processed by
var-specs. If it is #f, such keyword arguments are just ignored.
(define (proc x . options)
(let-keywords options ((a 'a)
(b :beta 'b)
(c 'c)
. rest)
(list x a b c rest)))
(proc 0)=> (0 a b c ())
(proc 0 :a 1)=> (0 1 b c ())
(proc 0 :beta 1)=> (0 a 1 c ())
(proc 0 :beta 1 :c 3 :unknown 4)=> (0 a 1 3 (unknown 4))
let-keywords, but the binding is done in the order of
var-specs. So each expr can refer to the variables bound by
preceding var-specs.
These let-keywords and let-keywords* are originally from Gauche.
(let ((var expr)) body ...)
(let ((var expr)) body ... var)
(dotimes (variable limit result) body ...)=>
(do ((tlimit limit)
(variable 0 (+ variable 1)))
((>= variable tlimit) result)
body ...)
(dolist (variable lexpr result) body ...)=>
(begin (for-each (lambda (variable) body ...) lexpr) (let ((variable '())) result))
set!. The result will be the same as set!.
&assertion is raised.
The proc should be the procedure name which uses this macro and is for
debugging purpose.
syntax->datum.with-syntax, the only difference is
that this macro can refer previous pattern of p as if let* can.
This can reduce nest level when users need to write multiple
with-syntax to refer bound syntax object.
lambda.(lambda (c) body ...). Where c
can be any character of lower case of ASCII alphabet.
(map (^z (* z z)) '(1 2 3 4 5))=> (1 4 9 16 25)
(lambda c body ...). Where c
can be any character of lower case of ASCII alphabet.
(map (^z* z*) '(1 2 3 4 5))=> ((1) (2) (3) (4) (5))
;; Scheme file
;; load shared library (on Windows the extension might be '.dll')
;; On Unix like environment, the shared library must be full path or
;; located in the same directory as the script.
;; On Windows it can be on PATH environment variable as well.
(define so-library (open-shared-library "my-quick-sort.so"))
(define quick-sort
(c-function so-library ;; shared library
void ;; return type
quicksort ;; exported symbol
;; argument types
;; if you need pass a callback procedure, 'callback' mark needs to
;; be passed to the arguments list
(void* size_t size_t callback)))
(let ((array (u8-list->bytevector '(9 3 7 5 2 6 1 4 8)))
;; callback procedure
(compare (c-callback int ;; return type
(void* void*) ;; argument types
(lambda (a b)
(- (pointer-ref-c-uint8 x 0)
(pointer-ref-c-uint8 y 0))))))
;; call c function. all loaded c functions are treated the same as
;; usual procedures.
(quick-sort array (bytevector-length array) 1 compare)
;; release callback procedure.
;; NOTE: callback won't be GCed so users need to release it manually
(free-c-callback compare)
array)
;; Close shared library.
(close-shared-library so-library)
;; End of Scheme file
/* C file, must be compiled as a shared library and named 'my-quick-sort.so' */
#include <stdlib.h>
#include <string.h>
#ifdef _MSC_VER
# define EXPORT __declspec(dllexport)
#else
# define EXPORT
#endif
static void quicksort_(uintptr_t base,const size_t num,const size_t size,
void *temp,int (*compare)(const void *,const void *))
{
size_t pivot = 0,first2last = 0,last2first = num-1;
while(pivot+1 != num && !compare(base+size*pivot,base+size*(pivot+1))){
pivot++;
}
if(pivot+1 == num){
return;
}
if(0 > compare(base+size*pivot,base+size*(pivot+1))){
pivot++;
}
while(first2last < last2first){
while(0 < compare(base+size*pivot,base+size*first2last)
&& first2last != num-1){
first2last++;
}
while(0 >= compare(base+size*pivot,base+size*last2first)
&& last2first){
last2first--;
}
if(first2last < last2first){
if(pivot == first2last || pivot == last2first){
pivot = pivot^last2first^first2last;
}
memcpy(temp,base+size*first2last,size);
memcpy(base+size*first2last,base+size*last2first,size);
memcpy(base+size*last2first,temp,size);
}
}
quicksort_(base,first2last,size,temp,compare);
quicksort_(base+size*first2last,num-first2last,size,temp,compare);
}
EXPORT int quicksort(void *base, const size_t num, const size_t size,
int (*compare)(const void *, const void *))
{
void *temp = malloc(size);
if(!temp){
return -1;
}
quicksort_((uintptr_t)base,num,size,temp,compare);
free(temp);
return 0;
}
=>
#vu8(1 2 3 4 5 6 7 8 9)
open-shared-library is depending on the
platform, for example if your platform is POSIX envirionment then it will use
dlopen. So the resolving the file depends on it. If you know the
absolute path of the shared library, then it's always better to use it.
If then internal process of the procedure failed and raise is #f then it
returns NULL pointer, if raise is #t then it raises an error.
".dll" in Windows, ".so" in Linux or Unix.
void bool char short int long long-long unsigned-short unsigned-int unsigned-long unsigned-long-long intptr_t uintptr_t float double void* char* wchar_t* int8_t int16_t int32_t int64_t uint8_t uint16_t uint32_t uint64_tThe return value will be converted corresponding Scheme value. Following describes the conversion;
bool
char*
wchar_t*
char
short int long long-long
unsigned-short unsigned-int unsigned-long unsigned-long-long
intptr_t uintptr_t
int8_t int16_t int32_t int64_t
uint8_t uint16_t uint32_t uint64_t
float double
void*
char returns a Scheme integer not Scheme character.
name must be a symbol indicating a exported C function name.
argument-types must be zero or more followings;
bool char short int long long-long unsigned-short unsigned-int unsigned-long unsigned-long-long size_t void* char* wchar_t* float double int8_t int16_t int32_t int64_t uint8_t uint16_t uint32_t uint64_t callback ___When the C function is called, given Scheme arguments will be converted to corresponding C types. Following describes the conversion;
bool
char short int long long-long unsigned-short
int8_t int16_t int32_t uint8_t uint16_t
unsigned-int unsigned-long uint32_t size_t
int64_t long-long
uint64_t unsigned-long-long
float
double
void* char*
void* and char* are actually treated the same, internally.
The conversion will be like this;
wchar_t*
callback
___ is for variable length argument and it must be the last position
of the argument type list, otherwise it raises an error.
c-function macro. The arguments are the same as c-function,
only argument-types must be a list of types.
(c-func (address pointer))This is equivalent of following C code;
c_func(&pointer)pointer can be a pointer object or a bytevector. If the second form is used, then the passing address is offset of offset. It is user's responsibility to make sure the given pointer has enough space when offset is passed. If the pointer is a bytevector and offset is more than the bytevector size, then an error is signaled.
c-function's
return-type.
argument-types must be zero or following;
bool char short int long long-long intptr_t unsigned-char unsigned-short unsigned-int unsigned-long-long uintptr_t int8_t int16_t int32_t int64_t uint8_t uint16_t uint32_t int64_t float double size_t void*The conversion of C to Scheme is the same as
c-function's
return-type.
NOTE: if the content of void* won't be copied, thus if you modify it in
the callback procedure, corresponding C function will get affected.
NOTE: callback doesn't support char* nor wchar_t*. It is because
the conversion loses original pointer address and you might not want it. So
it is users responsibility to handle it.
proc must be a procedure takes the same number of arguments as
argument-types list.
Created callbacks are stored intarnal static storage to avoid to get GCed.
This is because C functions which accept callback may hold the given callback
in their storage which could be outside of Sagittarius GC root. So it is
users' responsibility to release created callback to avoid memory leak. To
release callbacks, you need to use c-callback macro. The arguments are the same as c-callback,
only argument-types must be a list of types.
(integer->pointer 0)=> #<pointer 0x0>
&assertion.
&assertion.
&assertion.
pointer->object.
Converts Scheme object to pointer and pointer to Scheme object respectively.
The operations are useful to pass Scheme object to callbacks and restore
it.
void* deref(void **pointer, int offset) {
return pointer[offset];
}
If NULL pointer is given, it raises &assertion.
memset(3).
NOTE: the fill will be converted to an unsigned char by the
memset(3).
The allocated memory will be GCed.
malloc.
The allocated memory won't be GCed. So releasing the memory is users'
responsibility.
address,
you might break some codes.
int8 int16 int32 int64
uint8 uint16 uint32 uint64
char wchar short int long long-long
unsigned-char unsigned-short unsigned-int unsigned-long unsigned-long-long
intptr uintptr
float double
pointer
NOTE: if the type is flonum or double, then it returns
Scheme flonum
NOTE: if the type is pointer, then it returns Scheme FFI pointer.
pointer-ref-c-type
The type conversion is the same as c-function's return-type.
There is no direct procedures to handle C arrays. Following is an example
of how to handle array of pointers;
(import (rnrs) (sagittarius ffi))
(define (string-vector->c-array sv)
(let ((c-array (allocate-pointer (* (vector-length sv) size-of-void*))))
(do ((i 0 (+ i 1)))
((= i (vector-length sv)) c-array)
;; pointer-set-c-pointer! handles Scheme string (converts to UTF-8)
;; If you need other encoding, then you need to write other conversion
;; procedure.
(pointer-set-c-pointer! c-array (* i size-of-void*) (vector-ref sv i)))))
;; how to use
(let ((p (string-vector->c-array #("abc" "def" "ghijklmn"))))
(do ((i 0 (+ i 1)))
((= i 3))
;; deref handles pointer offset.
;; it can be also (pointer-ref-c-pointer p (* i size-of-void*))
(print (pointer->string (deref p i)))))
Following is an example for Scheme string to UTF-16 bytevector;
(import (rnrs) (sagittarius ffi))
;; Converts to UTF16 big endian (on little endian environment)
(define (string->c-string s)
(let* ((bv (string->utf16 s (endianness big)))
;; add extra 2 bytes for null terminated string
(p (allocate-pointer (+ (bytevector-length bv) 2))))
(do ((i 0 (+ i 2)))
((= i (bytevector-length bv)) p)
;; pointer-set-c-uint16! uses native endianness to set the value
;; so this is platform dependent code.
(pointer-set-c-uint16! p i
(bytevector-u16-ref bv i (endianness little))))))
size-of-void* bytes.
Sets the pointer value. This is useful to reuse the existing pointer object.
CAUTION: this operation is really dangerous so be aware of it!
(type name) (typename must be a symbol. If the second form is used, thenarraysize name) (structstruct-name name) (bit-fieldtype (name bit) ...) (bit-field(type endian) (name bit) ...)
alignment is an auxiliary syntax
and n must be an integer which must be either negative number or
one of 1, 2, 4, 8, or 16. This form
specifies the alignemtn of the struct. If the n is negative number,
then it uses platform default alignment, if it's one of the above number,
then the alignment is according to the given number.
The first form is the simple C type form. type must be a symbol and the
same as one of the c-function's return-types or callback.
Following describes the concrete example and the equivalent C structure:
(define-c-struct st
(int foo)
(callback fn))
#|
struct st
{
int foo;
void* fn; /* function pointer */
};
|#
The second form is defining C type array with size.
Following describes the concrete example and the equivalent C structure:
(define-c-struct st
(int array 10 foo))
#|
struct st
{
int foo[10];
};
|#
The third form is defining internal structure.
Following describes the concrete example and the equivalent C structure:
(define-c-struct st1
(int array 10 foo))
(define-c-struct st2
(struct st1 st)
(int bar))
#|
struct st1
{
int foo[10];
};
struct st2
{
struct st1 st;
int bar;
};
|#
So far, we don't support direct internal structure so users always need to
extract internal structures.
The forth and fifth forms are bit fields. type must be an integer
type such as unsigned-int. If the given type is not an integer,
then &assertion is raised.
Following describes the concrete example and the equivalent C structure:
(define-c-struct st1
(bit-field unsigned-int (a 10) (b 20)))
#|
struct st1
{
unsigned int a : 10;
unsigned int b : 20;
};
|#
If the fifth form is used, then endian must be an identifier which has
valid name for endianness macro. Then the created structure packs
the value according to the given endian.
If the total amount of bits is greater than given type, then
&assertion is raised.
NOTE: Even though, this can accept signed integer the returning value would
not be signed. It is safe to specify unsigned type.
The macro also defines accessors for the c-struct. Following naming rules are
applied;
size-of-foo.
define-c-struct.
Returns the size of given struct.
define-c-struct macro.
The optional argument inner-member-names can be passed to get inner
struct values.
Following describes how it works.
(define-c-struct in (int i) (char c)) (define-c-struct out (int i) (struct in in0)) (define out (allocate-c-struct out)) (out-i-set! out 100 'i) ;; -> unspecified (out-in0-set! out 200 'i) ;; -> unspecified (out-i-ref out) ;; -> 100 (out-in0-ref out 'i) ;; -> 200 (out-in0-ref out) ;; -> pointer object (indicating the inner struct address)
define-c-struct.
name must be a symbol and struct has the same member.
pointer should be a pointer allocated by allocate-c-struct with
struct.
Returns a member name's value of struct from pointer.
define-c-struct.
name must be a symbol and struct has the same member.
pointer should be a pointer allocated by allocate-c-struct with
struct.
Sets value to pointer offset of member name of struct.
() ((The first for defines nothing. If the rest of form is used and rest is not null, then it will recursively define. The second form's*new-p) rest ...) ((s*new-sp) rest ...) (new rest ...)
* defines new-p as void*.
The third form's s* defines new-sp as char*.
The forth form defines new as original.
Following example describes how to will be expanded approximately.
(define-c-typedef char (* char_ptr) byte (s* string)) => (begin (define char_ptr void*) (define byte char) (define string char*) )
bool char short int long long-long unsigned-short unsigned-int unsigned-long unsigned-long-long intptr_t uintptr_t size_t float double int8_t int16_t int32_t int64_t uint8_t uint16_t uint32_t uint64_t void*The values are platform dependent.
tail (1) like script shows how it works:
(import (rnrs) (getopt) (sagittarius filewatch) (prefix (binary io) binary:))
(define (tail file offset)
(define watcher (make-filesystem-watcher))
(define in (open-file-input-port file))
;; dump contents to stdout
(define (dump)
(let loop ()
(let ((line (binary:get-line in)))
(unless (eof-object? line)
(put-bytevector (standard-output-port) line)
(put-bytevector (standard-output-port) #vu8(10))
(loop)))))
(define size (file-size-in-bytes file))
;; move port position if the size if more than offset
(when (> size offset) (set-port-position! in (- size offset)))
;; dump first
(dump)
;; add path to file watcher
(filesystem-watcher-add-path! watcher file '(modify)
(lambda (path event) (dump)))
;; monitor on foreground.
(filesystem-watcher-start-monitoring! watcher :background #f))
;; this tail is not line oriented
;; it shows tail of the file from the given offset.
(define (main args)
(with-args (cdr args)
((offset (#\o "offset") #t "1024")
. rest)
(tail (car rest) (string->number offset))))
access
modify
delete
move
attribute
accessed
modified
deleted
moved
attribute
&assertion.
&assertion.
filesystem-watcher-stop-monitoring!.
inotify (7) and
poll (2). If users add too many paths, then it may reach the
maximum number of watch descriptor.
The IN_MOVED_FROM and IN_MOVED_TO flags are passed as
moved. So it is users responsibility to detect which file is
moved from and which file is moved to.
kqueue (2). This
implementation contains 3 major issues. Possibility of number of file
descriptor explosion, not access flag support, and no support of
directory monitoring.
The kqueue requires file descriptor per monitoring path. Thus if
the number of paths is large, then it reaches the maxinum number of file
descriptors. (NB: kern.maxfiles on FreeBSD).
kqueue doesn't support path access monitoring (e.g. IN_ACCESS
on inotify). So it is impossible to monitor file access.
Current implementation of (sagittarius filewatch) using kqueue
doesn't allow users to monitor directory. This is because by default,
kqueue doesn't provide facility to detect which file is added.
To do it, we need manual management. To keep our code as simple as possible,
we decided not to do it for now. This decision may be changed if there's
enough demands.
kqueue, thus the
same limitation as BSD Unix is applied.
access flag may or may not work on
Windows depending on the configuration of the platform.
Due to the lack of deletion detect, delete and move work the
same. Thus the monitoring handler may get both deleted and moved
even though it's only specified delete or move.
(define (call-with-input-string str proc)
(proc (open-input-string str)))
(define (call-with-output-string proc)
(let ((port (open-output-string)))
(proc port)
(get-output-string port)))
(define (with-input-from-string str thunk)
(with-input-from-port (open-input-string str) thunk))
(define (with-output-to-string thunk)
(let ((port (open-output-string)))
(with-output-to-port port thunk)
(get-output-string port)))
buffered-port and transcoded-port.;; example for input port
(import (rnrs) (sagittarius io) (clos user))
;; make a custom binary input port with 'read slot
(get-u8 (make <custom-binary-input-port>
:read (lambda (bv start count)
(bytevector-u8-set! bv start 1)
1)))
;; example for output port
(import (rnrs) (sagittarius io) (clos user))
;; user defined custom binary output port
(define-class <my-port> (<custom-binary-output-port>)
;; this port has own buffer
((buffer :init-form (make-bytevector 5 0))))
;; create the port
(let ((out (make <my-port>)))
;; set 'write slot
(slot-set! out 'write
(lambda (bv start count)
;; just get the first element of given bytevector
;; and set it to own buffer
(bytevector-copy! bv start (slot-ref out 'buffer) 0 count)
count))
;;
(put-bytevector out #vu8(1 2 3 4 5))
(slot-ref out 'buffer))
;; -> #vu8(1 0 0 0 0)
position procedure must accept 0 argument. The procedure should
return the position of the port.
set-position procedure must accept 2 argument, position
andwhence. Whence shall be a symbol of begin,
current or end. The procedure should set the position
of the port according to the given whence and position.
read procedure must accept 3 argument. bv or string,
start and count. The first argument is decided by the port
type. If the port is binary port, then bytevector bv is passed.
If the port is textual port, then string string is passed.
The procedure should fill given bv or string in count
data elements starting start. And return number of data filled.
write procedure must accept 3 argument. bv or string,
start and count. The first argument is decided by the port
type. If the port is binary port, then bytevector bv is passed.
If the port is textual port, then string string is passed.
The procedure should retrieve data from given bv or string
upto count data elements starting start. And return number
of data read.
ready procedure must accept 0 argument. The procedure should
return true value if the port is ready to read. Otherwise #f.
flush procedure must accept 0 argument. The procedure should
flush the port.
close procedure must accept 0 argument. The procedure should
close the port.
If the creating port is input port, then read must be set before
any port operation. If the creating port is output port, then write
must be set before any port operation. Other slots are optional.
:allocation option for define-class.:allocation option for
class slot definition, respectively.
The meta class must be used with :metaclass option of
define-class.
The mixin class must be a parent class.
Currently, we only support :instance and :class keywords.
The following code is the whole definition of this classes.
(define-class <allocation-meta> (<class>) ())
(define-method compute-getter-and-setter ((class <allocation-meta>) slot)
(cond ((slot-definition-option slot :allocation :instance)
=> (lambda (type)
(case type
((:instance) '())
((:class)
(let* ((init-value (slot-definition-option
slot :init-value #f))
(init-thunk (slot-definition-option
slot :init-thunk #f))
(def (if init-thunk (init-thunk) init-value)))
(list
(lambda (o) def)
(lambda (o v) (set! def v)))))
(else
(assertion-violation '<allocation-meta>
"unknown :allocation type"
type)))))
(else (call-next-method))))
(define-class <allocation-mixin> () () :metaclass <allocation-meta>)
:validator and observer options for
define-class.:validator is for before set the value to the slot so that user can check
the value if it's correct or not.
:observer is for after set the value to the slot so that user can check
which value is set to the slot.
(import (clos user) (sagittarius mop eql)) (define-generic eql-fact :class <eql-specializable-generic>) (define-method eql-fact ((n (eql 0))) 1) (define-method eql-fact ((n <integer>)) (* n (eql-fact (- n 1)))) (eql-fact 10)=> 3628800
<generic>.
To use eql specializer, generic functions must have this class as a metaclass.
slot-ref.
Following classes are specialised by default.
<hashtable> uses hashtable-ref<list> uses list-ref<string> uses string-ref<vector> uses vector-refstring->number as a
conversion procedure.
If the given object is character, it uses char->integer as a
conversion procedure.
run procedure invokes name process and waits until it ends.
Then returns process' exit status.
The call procedure invokes name process and continue the Scheme
process, so it does not wait the called process. Then returns process object.
If you need to finish the process, make sure you call the process-wait
procedure described below.
Both procedures' output will be redirects current-output-port and
current-error-port. If you need to redirect it other place use
create-process described below.
create-process procedure creates and invokes a process indicated
name. Keyword arguments decide how to invoke and where to redirect the
outputs.
If stdout is #f or non output-port and call? is #f then
create-process raises &assertion.
stdout keyword argument indicates the port where to redirect the standard
output of the process. This can be either binary output port or textual output
port.
stderr keyword argument indicates the port where to redirect the standard
error of the process. This can be either binary output port or textual output
port. If this argument is #f, then stdout will be used.
call? keyword argument decides the default behaviour. If this is #t and
reader is not a procedure, then the create-process uses
async-process-read. If this is #f and reader is not a procedure,
then it uses sync-process-read. If reader is provided, then it
uses given reader.
reader keyword argument must be procedure which takes 4 arguments,
process object, redirection of standard output and error, and transcoder
respectively. This procedure decides how to handle the output.
Note: on Windows, both standard output end error has limitation. So if you
replace the default behaviour, make sure you must read the output from the
process, otherwise it can cause deat lock.
transcoder keyword argument must be transcoder or #f. This can be used in
the procedure which specified reader keyword argument.
The procedure create-process creates a process and call it. The
returning value is depending on the above keyword parameters. If reader
and stdout is provided, then the result value is the value returned from
reader procedure. Otherwise the created process object.
call described above.
#f.
NOTE: The exit status are platform dependent. On Windows, the value will be
32 bit integer. On POSIX, the value will be 8 bit unsigned integer.
NOTE: On POSIX environment, timeout only works if the given
process is created by make-process related procedures. If the
process is created by pid->process, then it raises an error with
ECHILD.
process-kill
is called, then returning value is its status code. Otherwise -1.
If the keyword argument children? is given and if it's true value, then
the procedure kills the child processes. The process of killing child processes
is not the same between Windows and POSIX. On Windows, the process seeks all
possible child processes. On POSIX, it simply calls killpg (2).
GetExitCodeProcess which means
if the process returns STILL_ACTIVE(259), then this procedure
return #t even if the process itself is already terminated.
On POSIX, the procedure uses kill (2) sending 0 to check the
existance of the process.
(sagittarius process) provides shared memory for
simple IPC.
no-create is specified, and there is
no shared memory with given name, then &i/o-file-does-not-exist
is raised. If no-truncate is specified, then the created shared
memory is intact, otherwise it is truncted.
shared-memory->bytevector will be 0 length bytevector.
(sagittarius threads).
;;#<(sagittarius regex)> ;; this imports only reader macros
;; This form is only for backward compatibility
;; portable way for other R6RS implementation's reader.
#!read-macro=sagittarius/regex
(import (sagittarius regex)) ;; usual import for procedures
#/regex/i ;; (sagittarius regex) defines #/regex/ form
;; reader macro in it. it converts it
;; (comple-regex "regex" CASE-INSENSITIVE)
Writing reader macro on toplevel
(import (rnrs) (sagittarius reader)) (set-macro-character #\$ (lambda (port c) (error '$-reader "invliad close paren appeared"))) (set-macro-character #\! (lambda (port c) (read-delimited-list #\$ port))) !define test !lambda !$ !display "hello reader macro"$$$ !test$ ;; prints "hello reader macro"Writing reader macro in library and export it
#!compatible ;; make sure Sagittarius can read keyword
(library (reader macro test)
;; :export-reader-macro keyword must be in export clause
(export :export-reader-macro)
(import (rnrs) (sagittarius reader))
(define-reader-macro $-reader #\$
(lambda (port c)
(error '$-reader "unexpected close paren appeared")))
(define-reader-macro !-reader #\!
(lambda (port c)
(read-delimited-list #\$ port)))
)
#!read-macro=reader/macro/test ;; imports reader macro
!define test !lambda !$ !display "hello reader macro"$$$
!test$ ;; prints "hello reader macro"
If you need to use reader macro in your library code, you need to define it
outside of the library. The library syntax is just one huge list so Sagittarius
can not execute the definition of reader macro inside during reading it.
define-reader-macro macro associates char and proc as a
reader macro. Once it is associated and Sagittarius' reader reads it, then
dispatches to the proc with 2 arguments.
If non-term? argument is given and not #f, the char is marked as
non terminated character. So reader reads as one identifier even it it contains
the given char in it.
The first form is a convenient form. Users can write a reader macro without
explicitly writing lambda. The form is expanded to like this:
(define-reader-macro #\$ ($-reader args ...) body ...) ;; -> (define-reader-macro $-reader #\$ (lambda (args ...) body ...))Note: the name is only for error message. It does not affect anything.
define-dispatch-macro creates macro dispatch macro character char
if there is not dispatch macro yet, and associates subchar and proc
as a reader macro.
If non-term? argument is given and not #f, the char is marked as non
terminated character. So reader reads as one identifier even it it contains the
given char in it.
Note: the name is only for error message. It does not affect anything.
| Macro character | Terminated | Explanation |
|---|---|---|
| #\( | #t | Reads a list until reader reads #\). |
| #\[ | #t | Reads a list until reader reads #\]. |
| #\) | #t | Raises read error. |
| #\] | #t | Raises read error. |
| #\| | #t | Reads an escaped symbol until reader reads #\|. |
| #\" | #t | Reads a string until reader reads #\". |
| #\' | #t | Reads a symbol until reader reads delimited character. |
| #\; | #t | Discards read characters until reader reads a linefeed. |
| #\` | #t | Reads a next expression and returns (quasiquote expr) |
| #\, | #t | Check next character if it is @ and reads a next expression.
Returns (unquote-splicing expr) if next character was
@, otherwise (unquote expr) |
| #\: | #f | Only compatible mode. Reads a next expression and returns a keyword. |
| #\# | #t(R6RS mode) | Dispatch macro character. |
| Sub character | Explanation |
|---|---|
| #\' | Reads a next expression and returns (syntax expr). |
| #\` | Reads a next expression and returns (quasisyntax expr) |
| #\, | Check next character if it is @ and reads a next expression.
Returns (unsyntax-splicing expr) if next character was
@, otherwise (unsyntax expr) |
| #\! | Reads next expression and set flags described below.
|
| #\v | Checks if the next 2 characters are u and 8 and reads
a bytevector. |
| #\u | Only compatible mode. Checks if the next character is 8 and reads
a bytevector. |
| #\t and #\T | Returns #t. |
| #\f and #\F | Returns #f. |
| #\b and #\B | Reads a binary number. |
| #\o and #\O | Reads a octet number. |
| #\d and #\D | Reads a decimal number. |
| #\x and #\X | Reads a hex number. |
| #\i and #\I | Reads a inexact number. |
| #\e and #\E | Reads a exact number. |
| #\( | Reads a next list and convert it to a vector. |
| #\; | Reads a next expression and discards it. |
| #\| | Discards the following characters until reader reads |# |
| #\\ | Reads a character. |
| #\= | Starts reading SRFI-38 style shared object. |
| #\# | Refers SRFI-38 style shared object. |
| #\< | Reads expressions until '>' and imports reader macro from it. Note: if expressions contains symbol, which is illegal library name, at the end #<-reader can not detect the '>' because '>' can be symbol. So the error message might be a strange one. |
#!. Following describes details of those modes;
no-overwrite flag. With this mode, keywords are read as
symbols; for example, :key is just a symbol and users can not use
extended lambda syntax.
no-overwrite flag.
#< (...) > form and let reader
read above hash-bang, the read table will be reset. So following code will raise
a read error;
#!read-macro=sagittarius/regex #!r6rs #/regular expression/ ;; <- &lexical
#!reader=srfi/:49
define
fac n
if (zero? n) 1
* n
fac (- n 1)
(print (fac 10))
#!reader= specifies which reader will be used. For this example, it will
use the one defined in (srfi :49) library. For compatibility of the other
Scheme implementation, we chose not to use the library name itself but a bit
converted name.
(srfi :49), first remove all parentheses or brackets then replace spaces
to /.
define. However if you use the first form
then expr must be lambda and it accept one argument.
The defined reader will be used on read time, so it needs to return valid
expression as a return value of the reader.
NOTE: Only one reader can be defined in one library. If you define more than
once the later one will be used.
:export-reader keyword to the library export clause.
;; For Perl like
(cond ((looking-at (regex "^hello\\s*(.+)") "hello world!")
=> (lambda (m) (m 1))))
=>
world!
;; For Java like
(cond ((matches (regex "(\\w+?)\\s*(.+)") "123hello world!")) ;; this won't match
(else "incovenient eh?"))
The matches procedure is total match, so it ignores boundary matcher
'^' and '$'. The looking-at procedure is partial match, so
it works as if perlre.
| Construct | Matches |
|---|---|
| Characters | |
x
| The character x |
\\
| The backslash character |
\0n
| The character with octal value 0n (0 <= n <= 7) |
\0nn
| The character with octal value 0nn (0 <= n <= 7) |
\0mnn
| The character with octal value 0mnn (0 <= m <= 3, 0 <= n <= 7) |
\xhh
| The character with hexadecimal value 0xhh |
\uhhhh
| The character with hexadecimal value 0xhhhh |
\Uhhhhhhhh
| The character with hexadecimal value 0xhhhhhhhh. If the value exceed the maxinum fixnum value it rases an error. |
\t
| The tab character ('\u0009') |
\n
| The newline (line feed) character ('\u000A') |
\r
| The carriage-return character ('\u000D') |
\f
| The form-feed character ('\u000C') |
\a
| The alert (bell) character ('\u0007') |
\e
| The escape character ('\u001B') |
\cx
| The control character corresponding to x |
| Character classes | |
[abc]
| a, b, or c (simple class) |
[^abc]
| Any character except a, b, or c (negation) |
[a-zA-Z]
| a through z or A through Z, inclusive (range) |
[a-d[m-p]]
| a through d, or m through p: [a-dm-p] (union) |
[a-z&&[def]]
| d, e, or f (intersection) |
[a-z&&[^bc]]
| a through z, except for b and c: [ad-z] (subtraction) |
[a-z&&[^m-p]]
| a through z, and not m through p: [a-lq-z](subtraction) |
| Predefined character classes | |
.
| Any character (may or may not match line terminators) |
\d
| A digit: [0-9] |
\D
| A non-digit: [^0-9] |
\s
| A whitespace character: [ \t\n\x0B\f\r] |
\S
| A non-whitespace character: [^\s] |
\w
| A word character: [a-zA-Z_0-9] |
\W
| A non-word character: [^\w] |
| Boundary matchers | |
^
| The beginning of a line |
$
| The end of a line |
\b
| A word boundary |
\B
| A non-word boundary |
\A
| The beginning of the input |
\G
| The end of the previous match |
\Z
| The end of the input but for the final terminator, if any |
\z
| The end of the input |
| Greedy quantifiers | |
X?
| X, once or not at all |
X*
| X, zero or more times |
X+
| X, one or more times |
X{n}
| X, exactly n times |
X{n,}
| X, at least n times |
X{n,m}
| X, at least n but not more than m times |
| Reluctant quantifiers | |
X??
| X, once or not at all |
X*?
| X, zero or more times |
X+?
| X, one or more times |
X{n}?
| X, exactly n times |
X{n,}?
| X, at least n times |
X{n,m}?
| X, at least n but not more than m times |
| Possessive quantifiers | |
X?+
| X, once or not at all |
X*+
| X, zero or more times |
X++
| X, one or more times |
X{n}+
| X, exactly n times |
X{n,}+
| X, at least n times |
X{n,m}+
| X, at least n but not more than m times |
| Logical operators | |
XY
| X followed by Y |
X|Y
| Either X or Y |
(X)
| X, as a capturing group |
| Back references | |
\n
| Whatever the nth capturing group matched |
| Quotation | |
\
| Nothing, but quotes the following character |
\Q
| Nothing, but quotes all characters until \E |
\E
| Nothing, but ends quoting started by \Q |
| Special constructs (non-capturing) | |
(?:X)
| X, as a non-capturing group |
(?imsux-imsux)
| Nothing, but turns match flags on - off |
(?imsux-imsux:X)
|
X, as a non-capturing group with the given flags on - off |
(?=X)
| X, via zero-width positive lookahead |
(?!X)
| X, via zero-width negative lookahead |
(?<=X)
| X, via zero-width positive lookbehind |
(?<!X)
| X, via zero-width negative lookbehind |
(?>X)
| X, as an independent, non-capturing group |
(?#...)
| comment. |
\p and \P are supported. It is cooporated
with SRFI-14 charset. However it is kind of tricky. For example regex parser
can reads \p{InAscii} or \p{IsAscii} and search charset named
char-set:ascii from current library. It must have In or Is
as its prefix.
#/\w+?/i instead of
like this (regex "\\w+?" CASE-INSENSITIVE).
matches procedure attempts to match the entire input string against
the pattern of regex.
The looking-at procedure attempts to match the input string against the
pattern of regex.
(define (regex-replace-all pattern text replacement) (regex-replace-all (regex-matcher pattern text) replacement))Text must be string. Replacement must be either string or procedure which takes matcher object and string port as its arguments respectively. Replaces part of text where regex matches with replacement. If replacement is a string, the procedure replace text with given string. Replacement can refer the match result with `
$n`.
n must be group number of given pattern or matcher.
If replacement is a procedure, then it must accept either one or two
arguments. This is for backward compatibility.
The first argument is always current matcher.
If the procedure only accepts one argument, then it must return a string which
will be used for replacement value.
If the procedure accepts two arguments, then the second one is string output
port. User may write string to the given port and will be the replacement
string.
The regex-replace-first procedure replaces the first match.
The regex-replace-all procedure replaces the all matches.
regex procedure.i as a
flagx as a
flagm as a flags as a flagu as a flag.
NOTE: when this flag is set then pre defined charset, such as \d or
\w, expand it's content to Unicode characters. Following properties
are applied to charsets.
Ll and Other_Lowercase.
Lu and Other_Uppercase.
Lt.
L, Nl and
Other_Alphabetic.
Nd.
P.
Sm, Sc, Sk and
So.
Zs, Zl and Zp.
Cc, Cf, Co, Cn.
(import (rnrs) (sagittarius socket))
;; creates echo server socket with port number 5000
(define echo-server-socket (make-server-socket "5000"))
;; addr is client socket
(let loop ((addr (socket-accept echo-server-socket)))
(call-with-socket addr
(lambda (sock)
;; socket-port creates binary input/output port
;; make it transcoded port for convenience.
(let ((p (transcoded-port (socket-port sock)
;; on Sagittarius Scheme native-transcoder
;; uses utf8 codec for ASCII compatibility.
;; For socket programming it might be better
;; to specify eol-style with crlf.
;; But this sample just shows how it goes.
(native-transcoder))))
(call-with-port p
(lambda (p)
(put-string p "please type something\n\r")
(put-string p "> ")
;; gets line from client.
(let lp2 ((r (get-line p)))
(unless (eof-object? r)
(print "received: " r)
;; just returns message from client.
;; NB: If client type nothing, it'll throw assertion-violation.
(put-string p r)
(put-string p "\r\n> ")
;; waits for next input.
(lp2 (get-line p)))))))))
;; echo server waits next connection.
(loop (socket-accept echo-server-socket)))
AF_INET)
(ai_socktype SOCK_STREAM)
(ai_flags (+ AI_V4MAPPED AI_ADDRCONFIG)) (ai_protocol 0)make-client-socket
uses getaddrinfo(3) to look it up. The arguments node, service,
ai-family, ai-socktype, ai-flags and ai-protocol are
passed to getaddrinfo(3) as corresponding parameters. For more detail,
see reference of getaddrinfo(3).
Node is a network address, ex) "www.w3.org", "localhost", "192.168.1.1".
Service is a network service, ex) "http", "ssh", "80", "22".
Ai-family is an address family specifier. Predefined specifiers are listed
below.
AF_INET)
(ai_socktype SOCK_STREAM)
(ai_protocol 0)make-client-socket.
call-with-socket calls a procedure with socket as an argument.
This procedure is analogy with call-with-port.
shutdown-output-port and shutdown-input-port shutdown
output or input connection of a socket associated with port respectively.
make-server-socket.
Wait for an incoming connection request and returns a fresh connected client
socket.
This procedures is a thin wrapper of POSIX's accept(2).
If the calling thread is interrupted by thread-interrupt!, then
the procedure returns #f.
recv(2).
send(2).
SHUT_RD, SHUT_WR or SHUT_RDWR.
The socket-shutdown shutdowns socket.
peer then it uses socket-peer. If it is info,
then it uses socket-info
socket-info-values.
Converts given IP address object to human readable string.
socket-info-values.
Converts given IP address object to bytevector.
sendto (2).
recvfrom (2).
SO_NOSIGPIPE socket option is set to the created socket.
This procedure is a thin wrapper of socket (2).
socket-select.
This procedure is a thin wrapper of connect (2).
bind (2).
listen (2).
setsockopt (2).
socket-setsockopt!.
size must be an integer. If the value is positive number, then the
returning value is a bytevector whose element count is size and
contains the socket option converted to byte array. Otherwise it returns
an integer value.
thread-interrupt!.
This procedure is a thin wrapper of select (2).
socket-select.
timeout is the same as socket-select.
socket-read-select can be used to detect if the given sockets have
readable data.
socket-write-select can be used to detect if the given sockets are
still active.
socket-error-select can be used to detect if the given sockets are
readable data. This procedure might not be so interesting since it can be
done by socket-read-select.
family
socktype
flags
protocol
sockaddr
next
get-addrinfo.&i/o is raised.
This procedure is a thin wrapper of getaddrinfo (3).
sockaddr slot of given addrinfo.
The returning value can be used socket-recvfrom and socket-sendto.
&socket or &host-not-found. The first
condition is raised when socket related operation failed, for example
socket-send. The latter condition is raised when get-addrinfo is
failed.
NOTE: make-client-socket and make-server-socket may raise
&host-not-found when the given node or service is not a
valid value.
The condition hierarchy is the following:
&i/o
+ &host-not-found (node service)
+ &socket (socket)
+ &socket-connection
+ &socket-closed
+ &socket-read-timeout
+ &socket-port (port)
port-ready procedure is called on socket port and
select (2) failed.
NOTE: Read or write failure of socket port raises &i/o-read or
&i/o-write the same as other ports for compatibility.
NOTE2: This condition may be signalled when get-bytevector-all is
called on socket port since it checks whether or not the given port is ready.
thread-start! procedure.
The optional argument name gives the thread a name. The name can be
retrieved calling thread-name procedure. If the argument is not given,
then the make-thread procedures creates an unique name.
thread-terminate! does not return. Otherwise
thread-terminate! returns an unspecified value; the termination of
the thread will occur before thread-terminate! returns.
thread-join! returns
timeout-val if it is supplied, otherwise a "join timeout exception"
is raised. If the thread terminated normally, the content of the
end-result field is returned, otherwise the content of the end-exception
field is raised.thread-resume!.
EINTR and cancels blocking system call such
as select (2). Currently the only relevant procedure for this is
socket-select related procedures. See
socket library - Low level APIs.
Currently the procedure uses SIGALRM on POSIX environment. This
might be changed in future, so do not depend on the signal to interrupt
the call from outside of Sagittarius process.
On Windows, the procedure uses combination of WSAEventSelect and
WaitForMultipleObjects. So there is no way to interrupt from
outside of Sagittarius process.
condition-variable-signal! or
condition-variable-broadcast! is performed, and no later than the
timeout, if it's given.
&i/o-file-does-not-exist.
semaphore-close! and semaphore-destroy! behaves the
same on Windows.
Europe/Amsterdam.
If the given name is not found, then GMT is returned as the fallback.current-time,
is used.
This procedure considers daylight saving time (DST). Means, if the timezone
has DST, then the return value is depending on the when. For example,
Europe/Amsterdam has DST so if the when is in DST, then the
returning offset is 7200, otherwise 3600.
Europe/Amsterdam has 2 names, CET and CEST. If the
given when is in DST, then CEST is returned, otherwise CET
is returned.
(let ((tz (timezone "Europe/Dublin"))
(now (date->time-utc (make-date 0 0 0 0 24 7 2015 0)))
;; 1:00 - IST 1971 Oct 31 2:00u
(no-rule-past (date->time-utc (make-date 0 0 0 0 24 7 1971 0)))
;; 0:00 GB-Eire GMT/IST 1968 Oct 27
(rule-past (date->time-utc (make-date 0 0 0 0 24 7 1968 0))))
(timezone-short-name tz now) ;; => "GMT/IST"
(timezone-short-name tz no-rule-past) ;; => "IST"
;; no DST
(timezone-offset tz no-rule-past) ;; => 3600
(timezone-raw-offset tz) ;; => 0
(timezone-raw-offset tz no-rule-past) ;; => 3600
(timezone-raw-offset tz rule-past) ;; => 0
(timezone-short-name tz rule-past) ;; => "GMT/IST"
)
3600 which is UTC+1 however if it's summer time, then the returning
list doesn't contain some of timezones (e.g. Amsterdam).
The optional argument when specifies the time to consider. If it's not
specified, then the returning value of current-time is used.
(zone-offset->timezones 3600) ;; => '(#<timezone Etc/GMT-1> ...) ;; offset +15:00 doesn't exist (zone-offset->timezones (* 15 3600)) ;; => '()
zone-offset->timezones*, the difference is
this procedure creates an anonymous timezone if there's no registered timezone
matching with the given offset.
(zone-offset->timezones* 3600) ;; => '(#<timezone Etc/GMT-1> ...) ;; offset +15:00 doesn't exist (zone-offset->timezones* (* 15 3600)) ;; => '(#<timezone +15:00>)
(debug-print expr)
debug-print is an internal macro of this library which prints the
read expression and its result.
Following example shows how to enable this;
#!read-macro=sagittarius/debug #!debug (let ((a (+ 1 2))) #?=(expt a 2)) #| #?=(expt a 2) #?- 9 |#
#!debug enables the debug print.
syntax-rules. It doesn't consider
locally bound macros.
The returning value may or may not be used as proper Scheme expression.
null-generator,
all procedures have prefix 'g'. Arguments named generator
indicates a generator.
(generator->list (giota 5))=> (0 1 2 3 4)
(generator->list (giota 5 10))=> (10 11 12 13 14)
(generator->list (giota 5 10 2))=> (10 12 14 16 18)
unfold.
(generator->list (gunfold
(lambda (s) (> s 5))
(lambda (s) (* s 2))
(lambda (s) (+ s 1))
0))
=>
(0 2 4 6 8 10)
reverse-vector->generator which return end to beginning.
port->char-generator uses get-char
to read the port. The port->byte-generator uses get-u8.
<list>, <vector>, <string>, <bytevector> and
<port>.
If the given argument is type of <vector>, then vector->generator
is used. If the given argument is type of <port>, then it checks if
it's binary or textual and dispatches apropriate procedure.
(proc v1 v2 ... seed), where
v1, v2,... are the values yielded from the input
generators, and seed is the current seed value. It must return two
values, the yielding value and the next seed.
gtake is passed, then the value
is filled until the procedure reaches k.
These procedures are analogues of SRFI-1 take and drop.
take-while
and drop-while.
(generator->list (gindex (list->generator '(a b c d e f))
(list->generator '(0 2 4))))
=>
(a c e)
(generator->list (gselect (list->generator '(a b c d e f))
(list->generator '(#t #f #f #t #t #f))))
=>
(a d e)
(apply gappend (generator->list generator))The difference is that this procedure can handle infinite generator.
(generator->list (gflatten (list->generator (list '(1 2 3 4)
'(a b c d)
'(A B C D)))))
=>
(1 2 3 4 a b c d A B C D)
(generator->list (gflatten (list->generator (list 'ignored
'(a b c d)
'ignored
'(A B C D)))))
=>
(a b c d A B C D)
gmerge procedure is called only one argument, then
it simply returns a generator (if generator1 isn't a generator then
it is coerced).
(generator->list (gmerge < (list->generator '(1 4 5)) (list->generator '(0 2 3))))=> (0 1 2 3 4 5)
proc.
The proc is called with the items returned by generator1 and
generator2 if it's given.
The gmap procedure accepts uneven length of generators however one
of the generator must be finite length, otherwise it won't be exhausted.
It is an analogy of map.
proc.
This procedure is similar with gmap. The difference is that the
returning item is filtered if the returning value of proc is #f.
It is an analogy of filter-map.
(define g
(make-coroutine-generator
(lambda (yield)
(let loop ((i 0))
(when (< i 3)
(yield i)
(loop (+ i 1)))))))
(generator->list g)
=>
(0 1 2)
glet* is a macro which is similar to let*. The difference
is that glet* check if the bindings are EOF object or not and if it
detects EOF object, then it returns EOF object immediately.
bindings must be one of the following forms:
(var gen-expr)
( gen-expr )
glet* just check if the value is EOF or not.
(define g (list->generator '(1 2 3))) (list (glet* ((a (g))) a) (glet* ((a (g))) (define b 2) (+ a b)) (glet* ((a (g)) (b (g))) (+ a b)))=> (1 2 #<eof>)
glet*. This is defined
like the following:
(define-syntax glet1
(syntax-rules ()
((_ var expr body body1 ...)
(glet* ((var expr)) body body1 ...))))
tar and zip.
(import (rnrs) (archive))
;; extract file "bar.txt" from "foo.zip"
(call-with-input-archive-file 'zip "foo.zip"
(lambda (zip-in)
(do-entry (e zip-in)
(when (string=? (archive-entry-name e) "bar.txt")
(call-with-output-file "bar.txt"
(lambda (out) (extract-entry e out))
:transcoder #f)))))
;; archive "bar.txt" into foo.tar
(call-with-output-archive-file 'tar "foo.tar"
(lambda (tar-out)
(append-entry! tar-out (create-entry tar-out "bar.txt"))))
Following sections use type as a supported archive type. More precisely,
if it's a supported archive type then there must be a library named
(archive type).
(do ((entry (next-entry! archive-input) (next-entry! archive-input)))
((not entry) result)
body ...)
If the first form is used, then result is #t.
finish!.
call-with-input-archive.
call-with-input-archive-port.
(define-method create-entry ((out <archive-output>) file) (create-entry out file file))So as long as it doesn't have to be distinguished, users don't have to implement this method.
finish!.
call-with-output-archive.
call-with-output-archive-port.
file or
directory.
(archive interface).
So the library code should look like this;
(library (archive foo)
(export) ;; no export procedure is needed
(import (rnrs)
(close user)
(archive interface)
;; so on
...)
;; class and method definitions
...
)
For archiving, the implementation needs to implement following methods and
extends following classes;
make-archive-input, next-entry, extract-entry
<archive-input> <archive-entry>For extracting, the implementation needs to implement following methods and extends following classes;
make-archive-output, create-entry, append-entry!, finish!
<archive-output> <archive-entry>NOTE:
<archive-entry> may be shared between archiving and extracting.
file or
directory.
eql specializer to specify.
finish! method for archive input has a default
implementation and it does nothing.
Users can specialize the method for own archive input.
(asn.1) library. The library supports DER and BER
formats. We do not describe DER or BER format here.
&assertion
<der-encodable>.
<der-encodable>.
<der-encodable>.
<der-encodable>.
(asn.1)
library.
define-simple, the
reader is simple-read and the write is simple-write,
Then the definition of defined macro would be like this;
define-composite, the
reader is simple-read and the write is simple-write,
Then the definition of defined macro would be like this;
define-class however slots must be a list
of one of the followings.
eqv? comparable datum. e.g. keyword.
default can be any object.
count must be a non negative exact integer.
The first form is equivalent with the following form;
(name type #f).
And the third form is equivalent with the following form;
(name (type count) #f).
The first 2 forms defines a datum slot which the datum is read by reader
passing type and written by writer.
The rest forms defines an array data represented by a vector.
If the type is not defined by neither of the definition forms, then
it is users responsibility to define a method which handles the type.
(import (clos user) (binary data))
;; use the same name of reader and writer
(define-simple-datum-define define-simple sample-read sample-write)
(define-composite-data-define define-composite sample-read sample-write)
(define-simple <simple> ()
(a b (c 0))
(lambda (in) (values (get-u8 in) (get-u8 in) (get-u8 in)))
(lambda (out a b c) (put-u8 out a) (put-u8 out b) (put-u8 out c)))
(define-composite <composite> ()
((d :byte 1)
(e (:byte 4) #vu8(1 2 3 4))
(f <simple>)))
;; :byte reader and writer
(define-method sample-read ((o (eql :byte)) in array-size?)
(if array-size?
(get-bytevector-n in array-size?)
(get-u8 in)))
(define-method sample-write ((type (eql :byte)) o out array-size?)
(if array-size?
(put-bytevector out o)
(put-u8 out o)))
How to use the defined data structure.
;; read as a <composite> object
;; "deeeeabc" in ascii
(define bv #vu8(#x64 #x65 #x65 #x65 #x65 #x61 #x62 #x63))
(call-with-port (open-bytevector-input-port bv)
(lambda (in)
(let ((s (sample-read <composite> in)))
(slot-ref s 'd) ;; => #\d
(slot-ref s 'f) ;; => <simple>
)))
;; write <composite> object
(call-with-bytevector-output-port
(lambda (out)
(let* ((s (make <simple> :a 10 :b 20))
(c (make <composite> :f s)))
;; this can be written like this as well (sample-write o out)
(sample-write <composite> c out))))
;; => #vu8(1 1 2 3 4 10 20 0)
get-line for binary port).
This library exports those convenient procedures
#vu8(#x0d #x0a). Default value is
#vu8(#x0a)
If keyword argument transcoder is given, then returning value will be
converted to string.
(sagittarius) for convenience. See
Sagittarius extensions.
endianness macro.
Write v to out as unsigned/signed 16/32/64 bit integer or
32/64 bit floating number.
(sagittarius) for convenience. See
Sagittarius extensions.
endianness macro.
Read a number from in as unsigned/signed 16/32/64 bit integer or
32/64 bit floating number.
+default-chunk-size+ is used.
(weinholt struct pack) library.
(pack "!c" 128)=> #vu8(128)
(pack "s" 100)=> #vu8(100 0)
(pack "!s" 100)=> #vu8(0 100)
(pack "!d" 3.14)=> #vu8(64 9 30 184 81 235 133 31)
(pack "!xd" 3.14)=> #vu8(0 0 0 0 0 0 0 0 64 9 30 184 81 235 133 31)
(pack "!uxd" 3.14)=> #vu8(0 64 9 30 184 81 235 133 31)
#\* means
indefinite length repetition.
(pack "3c" 1 2 3)=> #vu8(1 2 3)
(pack "*c" 1 2 3 4)=> #vu8(1 2 3 4)
(pack "3c" 1 2 3 4)=> &syntax
(pack (car '("3c")) 1 2 3 4)
=>
&error
pack!.
If the second form is used, then unpacking is done from the given offset.
(unpack "!SS" #vu8(0 1 0 2))=> 1 2
(unpack "!SS" #vu8(0 1 0 2 0 3) 1)=> 2 3
(unpack "!uSS" #vu8(0 1 0 2 0 3) 1)=> 256 512
#\*, otherwise #f is returned.
(format-size "!xd")=> 16
(format-size "!uxd")=> 9
(format-size "*c")=> #f
(format-size "*c" 1 2 3 4)=> 4
pack and unpack are syntactic keywords.
Defines packing extension to given char. This macro can not overwrite
the predefined characters. ** can be followings;
s8, u8, s16, u16, s32, u32,
s64, u64, f32, and f64.
;; defining char to u8 converter (define-u8-packer (#\A v) (pack (char->integer v)) (unpack (integer->char v))) (pack "AA" #\a #\b) ;; => #vu8(97 98) (unpack "AA" #vu8(97 98)) ;; => #\a #\b
buffer and size fields.
buffer field of given buffer.
The type of buffer field is implementation specific.
size field of given buffer.
The returning value shall represents how much buffer of the given buffer
is consumed.
size field of given buffer.data field which contains overflowing data.
&pre-allocated-buffer-overflow
condition, otherwise #f.
data field value of condition.
The condition must be a &pre-allocated-buffer-overflow condition.
<pre-allocated-buffer>.
bytevector-u8-set!
bytevector-u16-set!
bytevector-u32-set!
bytevector-u64-set!
bytevector-s8-set!
bytevector-s16-set!
bytevector-s32-set!
bytevector-s64-set!
bytevector-ieee-single-set!
bytevector-ieee-double-set!
The endianness is passed to the above procedures if required.
This procedure also updates the size field of binary-buffer.
(- (bytevector-length bv) start).
This procedure also updates the size field of binary-buffer.
bytevector-u8-set!
bytevector-s8-set!
bytevector-u16-set!
bytevector-u32-set!
bytevector-u64-set!
bytevector-s16-set!
bytevector-s32-set!
bytevector-s64-set!
bytevector-ieee-single-set!
bytevector-ieee-double-set!
The endianness is passed to the above procedures if required.
This procedure updates the size field of binary-buffer if
sum of given index and number of bytes set in the buffer exceeds
the size of the buffer.
(- (bytevector-length bv) start).
This procedure updates the size field of binary-buffer if
sum of given index and number of bytes set in the buffer exceeds
the size of the buffer.
&pre-allocated-buffer-overflow,
when it tries to exceed the pre-allocated buffer.
size field value of buffer field.
&pre-allocated-buffer-overflow.
bytevector->integer.
All procedures take bytevector as its arguments.
! freshly allocate a new bytevector as it's return
value. If the given bytevectors are not the same sized, then the smallest
size will be allocated.
The procedures with ! takes first argument as the storage of the result
and return it.
(bytevector-slices #vu8(1 2 3 4 5 6) 3)=> (#vu8(1 2 3) #vu8(4 5 6))
(bytevector-slices #vu8(1 2 3 4) 3)=> (#vu8(1 2 3) #vu8(4))
;; the given bytevector bv is #vu8(4) (bytevector-slices #vu8(1 2 3 4) 3 :padding (lambda (bv) #vu8(4 5 6)))=> (#vu8(1 2 3) #vu8(4 5 6))
;; this is valid as well so that bytevector-slices doesn't check the ;; return value (bytevector-slices #vu8(1 2 3 4) 3 :padding (lambda (bv) #f))=> (#vu8(1 2 3) #f)
(bytevector-split-at* #vu8(1 2 3 4 5) 3)=> #vu8(1 2 3) and #vu8(4 5)
(bytevector-split-at* #vu8(1 2) 3 :padding (lambda (bv) #vu8(1 2 3)))=> #vu8(1 2 3) and #vu8()
(bytevector-split-at* #vu8(1 2) 3 :padding (lambda (bv) #f))=> #f and #vu8()
0. The comparison procedures are <, >, <=
and >=, respectively.
(list->string (map integer->char (bytevector->u8-list bv)))This procedure is implemented in a memory efficient way.
bytevector-reverse! reverses destructively.
0 <= n <= 255.
This is useful to handle bytevectors as if they are ASCII strings.
0 <= o <= 255, otherwise #f.u8?. Otherwise #f.
u8-set?. u8 should satisfy
u8. The procedure doesn't check if arguments satify this.
Returns #t if given u8-set contains u8.
u8-set?.
It is users' responsibility to pass ASCII string.
u8-set? by dropping outside of ASCII characters.
bytevector-take takes from left and the bytevector-take-right
takes from right.
bytevector-drop drops from left and the bytevector-drop-right
drops from right.
" \r\f\v\n\t".
The optional arguments start and end specify from and until where
the procedure trims. The default value is 0 for start and the length
of given bytevector for end.
bytevector-pad pads left side of given bv. The
bytevector-pad-right pads right side of given bv.
The optional arguments start and end specify from and until where
the procedure pads. The default value is 0 for start and the length
of given bytevector for end.
(bytevector-append (bytevector-copy s1 0 start1)
(bytevector-copy s2 start2 end2)
(bytevector-copy s1 end1 (string-length s1)))
(util concurrent). This library provides
future related APIs.(import (rnrs) (util concurrent)) ;; creates 5 futures (define futures (map (lambda (i) (future (* i i))) '(1 2 3 4 5))) ;; wait and retrieve the results (map future-get futures)=> (1 4 9 16 25)
(future (class <simple-future>) expr ...)
<simple-future> provides by
this library won't disturb the execution. Thus calling this procedure
doesn't do anything but changing the future's state.
NOTE: once this procedure is called, then calling future-get
with future raises a &future-terminated.
(import (rnrs) (util concurrent)) (define f (future (display "cancelled") (newline))) (future-cancel f) (future-get f)=> &future-terminated
"cancelled".
future-cancel, otherwise #f.done and terminated.
done is set when future-get is called.
terminated is set when future-cancel is called.
&future-terminated.
&future-terminated condition.
Retrieve terminated future from condition.
<future> implementation of this library.(util concurrent). This library provides
executor related APIs.java.util.concurrent package. The library provides 2 types
of executors, thread pool executor and fork join executor. The first
one uses thread pool, described below section, and the latter one
just creates a thread per task. The following is an example how to use
the executors:
(import (rnrs) (util concurrent))
;; creates executor which uses 5 threads and push all tasks
(define executor
(make-thread-pool-executor 5 push-future-handler))
;; creates 10 futures
(define futures
(map (lambda (i)
(future (class <executor-future>)
(* i i)))
'(1 2 3 4 5 6 7 8 9 10)))
;; execute futures
(for-each (lambda (future) (execute-future! executor future)) futures)
;; wait/retrieve the results
(map future-get futures)
=>
(1 4 9 16 25 36 49 64 81 100)
push-future-handler waits until the
previous taskes are finished.
state.
state field of the executor.(define (executor-submit! e thunk)
(let ((f (make-executor-future thunk)))
(execute-future! e f)
f))
(util concurrent thread-pool) as its
underlying thread managing. So once the threads are created then the
thread holds its environment until the executor is shutdown. In other
words, if a task changes the dynamic environment, then the next task
uses the changed dynamic environment. The following example describes
how dynamic environments works on this executor:
(import (rnrs) (util concurrent) (srfi :39))
(define *one* (make-parameter 1))
(define executor (make-thread-pool-executor 1))
(let ((f1 (make-executor-future (lambda () (*one* 2) 1)))
(f2 (make-executor-future (lambda () (*one*)))))
(execute-future! executor f1)
(future-get f1)
(execute-future! executor f2)
(future-get f2))
=>
2
*one* is initialised with
the initial value 1 during thread creation.
<executor>.abort-rejected-handler is used.
push-future-handler
is specified during the executor creation.
push-future-handler is specified.
&rejected-execution-error.
This is the default handler.
abort-rejected-handler is called.
&rejected-execution-error object.
Otherwise #f.&rejected-execution-error object.
Retrieves the rejected future and executor, respectively.
<simple-future>.
<executor>.shutdown.<executor-future>. This type inherits
<future>.
(util concurrent). This library provides
thread pool APIs.(import (rnrs) (util concurrent)) ;; pooling 5 thread (define thread-pool (make-thread-pool 5)) (for-each (lambda (i) (thread-pool-push-task! thread-pool (lambda () (* i i)))) '(1 2 3 4 5 6 7 8 9 10)) ;; waits until all tasks are done (thread-pool-wait-all! thread-pool) ;; release thread-pool (thread-pool-release! thread-pool)
thread-pool-thread procedure.
terminate, then the procedure
terminates the thread instead of joining.
NOTE: terminating a thread is very dangerous operation, so don't use casually.
(thread-pool-current-thread-id) procedure to retrieve thread id from
managed threads.
It signals an error if the given thread is not a managed thread.
NOTE: if the thread is terminated, then the procedure also signals an error.
(util concurrent). This library provides
shared queue APIs.(import (rnrs) (util concurrent) (srfi :18))
(define shared-queue (make-shared-queue))
(define thread
(thread-start!
(make-thread
(lambda ()
;; waits until the queue has an element
(let ((value (shared-queue-get! shared-queue)))
(* value value))))))
(shared-queue-put! share-queue 5)
(thread-join! thread)
=>
25