If 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.