Yes, this is very helpful. Thank you. -Jon
On Fri, Sep 12, 2014 at 10:47 AM, Matthias Felleisen <matth...@ccs.neu.edu> wrote: > > Does this sketch help: > > #lang racket > > ;; define a header file language > (module L racket > ;; specification > (provide export) > ;; ---------------------------------------------- > ;; implementation > (define-syntax (export stx) > (syntax-case stx () > [(_ file name ctc) > #'(define-syntax (file stx) > (syntax-case stx () > [(_) > ;; let's break hygiene here: > (let* ([x '(provide (contract-out (name ctc)))] > [y (datum->syntax stx x)]) > y)]))]))) > > ;; ------------------------------------------------------- > (module header-file racket > (require (submod ".." L)) > (provide provide-stack) > ;; ----------------------------------------------------- > (export provide-stack make (-> empty?))) > > (module good-server racket > (require (submod ".." header-file)) > (provide-stack) > ;; ----------------------------------------------------- > (define (make) > '())) > > (module bad-server racket > (require (submod ".." header-file)) > (provide-stack) > ;; ----------------------------------------------------- > (define (make) > "the empty stack")) > > (module client racket > (provide > (contract-out > (test (-> (values string? string?))))) > ;; ----------------------------------------------------- > (require (prefix-in good: (submod ".." good-server)) > (prefix-in bad: (submod ".." bad-server))) > > (define (test) > (values > (with-handlers ((exn:fail:contract? (lambda (_) "passed"))) > (bad:make) > "failed") > (begin (good:make) "passed")))) > > ;; RUN BABY RUN > (require 'client) > (test) > > > > ____________________ Racket Users list: http://lists.racket-lang.org/users
