Not built-in. That's what I wished #:auto was, but alas that's not what Racket has. I think common practice is to forget #:auto ever existed. -Ian ----- Original Message ----- From: "Spencer Florence" <[email protected]> To: "J. Ian Johnson" <[email protected]> Cc: "racket" <[email protected]> Sent: Tuesday, July 29, 2014 5:43:52 PM GMT -05:00 US/Canada Eastern Subject: Re: [racket] Shared and structs with #:auto
Woops. I was under the impression that #:auto worked like an optional argument. Is there any way to do optional constructor arguments with structs (I don't see one but I can hope...)? On Tue, Jul 29, 2014 at 4:39 PM, J. Ian Johnson < [email protected] > wrote: >From the struct docs: constructor-id (which defaults to id), a constructor procedure that takes m arguments and returns a new instance of the structure type, where m is the number of fields that do not include an #:auto option. You don't give anything to the constructor for #:auto fields. -Ian ----- Original Message ----- From: "Spencer Florence" < [email protected] > To: "racket" < [email protected] > Sent: Tuesday, July 29, 2014 5:32:46 PM GMT -05:00 US/Canada Eastern Subject: [racket] Shared and structs with #:auto Hi all, I'm trying to use shared with a structure that has a field with #:auto If I have some structure like this: (struct test ([a #:auto]) #:transparent #:mutable) this works fine: (shared ([b (test)]) b) but this errors: (shared ([b (test 1)]) b) with "shared: wrong argument count for structure constructor; expected 0, found 1 in: (test1 1)" Is this a bug? Is there a work around? --Spencer ____________________ Racket Users list: http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
