commander-s/scheme/scheme-commands.scm

(define command-prefix #\,)

(define (split-scheme-command-line command-line)
  (let ((tokens (string-tokenize command-line)))
    (values (string-drop (car tokens) 1)
            (cdr tokens))))

(define (scheme-command-line? command-line)
  (char=? (string-ref (string-trim command-line) 0) 
          command-prefix))

(define (eval-scheme-command command args)
  (case (string->symbol command)
    ((in)
     (set-evaluation-package! (string->symbol (car args)))
     (string-append "moved to package " (car args)))
    ((open)
     (package-open! 
      (evaluation-environment)
      (lambda () 
        (environment-ref
         (config-package) (string->symbol (car args)))))
     (string-append "opened package " (car args)))
    ((user)
     (set-evaluation-package! 'nuit-eval)
     "moved to package nuit-eval")
    ((inspect)
     (if (null? args)
         ",inspect requires an argument"
         (make-inspection-object 
          (eval-string (string-join args)))))
    ((exit)
     (exit))
    (else (error "unknwon scheme command" command))))