Yes, it appears that `racket/signature` exports a `struct` that is consistent with `define-struct` instead of `struct`.
I'm not sure whether that was a bug that didn't get caught, or whether it was intentional (for some kind of compatibility) and was documented incorrectly. My guess is that it was the former, originally; at this point, it has to be the latter, since I don't want to break code that's using `racket/signature`. So, I'll fix the documentation. At Wed, 4 Feb 2015 22:47:31 -0500, Justin Zamora wrote: > 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" <matth...@ccs.neu.edu> 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 ____________________ Racket Users list: http://lists.racket-lang.org/users
