<div dir="ltr">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...)?</div><div class="gmail_extra"> <div class="gmail_quote">On Tue, Jul 29, 2014 at 4:39 PM, J. Ian Johnson <<a href="mailto:ianj@ccs.neu.edu" target="_blank">ianj@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> >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 <div><div class="h5">----- Original Message ----- From: "Spencer Florence" <<a href="mailto:florence@northwestern.edu">florence@northwestern.edu</a>> To: "racket" <<a href="mailto:users@racket-lang.org">users@racket-lang.org</a>> 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 </div></div>____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div> </div>