a racket #lang for multiple files in one
documentation: http://docs.racket-lang.org/multi-file-lang/index.html
Example:
#lang multi-file
#file a.rkt
#lang racket/base
(provide x f)
(define x 3)
(define (f x) (string-append "hello" (make-string x #\!)))
(f 1)
#file b.rkt
#lang racket/base
(require "a.rkt")
x
(f x)