Yes, I had a copy/paste error in my previous message. The struct definition in the unit matches the one in the signature. I think that Daniel identified the core problem that the constructor is defined differently in #lang racket/signature.
Justin On Feb 4, 2015 9:31 PM, "Matthias Felleisen" <[email protected]> wrote: > > This works: > > ;; --------------------------------------------------------- > #lang racket/signature ;; b-sig.rkt > > (struct spelling-word (word sentence word-number lesson word-list)) > b-value > > ;; --------------------------------------------------------- > #lang racket/unit ;; b-unit.rkt > > (require "b-sig.rkt") > > (import) > (export b^) > > (define-struct spelling-word (word sentence word-number lesson word-list)) > > (define b-value 3) > > > ;; --------------------------------------------------------- > The signature of a component (unit) describes the names of the exports > (or imports). So when you write > > (struct my-struct (a b c)) > > in a signature, your exporting unit must define something like > > (define-struct my-struct (a b c)) > > [You can also use the struct syntax but you then need to define the > alternative constructor.] > > ;; --------------------------------------------------------- > I recommend developing small units in one DrRacket buffer. It's the > easiest way to get used to their syntax. > > -- Matthias > > > > > > > > On Feb 4, 2015, at 9:14 PM, Justin Zamora wrote: > > > There seems to be a problem exporting struct constructors when using > #lang racket/signature. This works: > > > > ----- b-sig.rkt----- > > #lang racket > > > > (define-signature b^ > > ((struct my-struct (a b c)) > > b-value)) > > > > (provide b^) > > > > ----- b-unit.rkt ----- > > #lang racket/unit > > > > (require "b-sig.rkt") > > > > (import) > > (export b^) > > > > (struct spelling-word > > (word sentence word-number lesson word-list)) > > > > (define b-value 3) > > > > But if you change b-sig to use #lang racket/signature: > > #lang racket/signature > > > > (struct my-struct (a b c)) > > b-value > > > > then running b-unit produces the error: > > > > Welcome to DrRacket, version 6.1 [3m]. > > Language: racket/unit; memory limit: 512 MB. > > define-unit: undefined export make-my-struct in: (define-unit b@ > (import) (export b^) (struct my-struct (a b c)) (define b-value 3)) > > > > Is this a just a bug or am I missing something? > > > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > >
____________________ Racket Users list: http://lists.racket-lang.org/users
