Neil, I think this is a current limitation in TR. Can not case-> (i.e. spec optional args) along with KW args. From a previous email chain: <div> </div><div><div class="im" style="color:rgb(80,0,80);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"> On Fri, Aug 10, 2012 at 3:12 AM, Eric Dobson <<a href="mailto:eric.n.dobson@gmail.com" style="color:rgb(17,85,204)">eric.n.dobson@gmail.com</a>> wrote: </div><div class="im" style="color:rgb(80,0,80);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"> > It looks like there is an issue with turning case lambdas with > keywords into a contract. If you drop the one argument case for > function, it should work. </div>Sam: "Unfortunately, the `case->` contract combinator that Typed Racket relies on doesn't support keyword arguments, so it's very difficult to generate an appropriate contract here." <div class="gmail_quote">On Sun, Aug 12, 2012 at 8:35 PM, Neil Toronto <<a href="mailto:neil.toronto@gmail.com" target="_blank">neil.toronto@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On 08/12/2012 06:14 PM, Ray Racine wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Just completed a first cut draft TRing the Plot collection. Completely untested, though the few things I've tried worked fine. Neil/Sam, any suggestions, naming or layout conventions are much appreciated. Otherwise, I'll do a cleanup pass, test it, and initiate a pull-request this week. <a href="https://github.com/RayRacine/racket/tree/tr-plot/collects/typed/plot" target="_blank">https://github.com/RayRacine/racket/tree/tr-plot/collects/typed/plot</a> </blockquote> </div></div> Cool! This is probably going to annoy you, but the `Option' type doesn't mean the argument isn't required. The entry for `surface3d' is currently [surface3d ((Real Real -> Real) (Option Exact-Rational) (Option Exact-Rational) (Option Exact-Rational) (Option Exact-Rational) .... -> Renderer3d)] where `....' represents the keyword argument types. To account for the possible argument combinations, it should be [surface3d (case-> ((Real Real -> Real) .... -> Renderer3d) ((Real Real -> Real) (Option Exact-Rational) .... -> Renderer3d) ((Real Real -> Real) (Option Exact-Rational) (Option Exact-Rational) .... -> Renderer3d) ((Real Real -> Real) (Option Exact-Rational) (Option Exact-Rational) (Option Exact-Rational) .... -> Renderer3d) ((Real Real -> Real) (Option Exact-Rational) (Option Exact-Rational) (Option Exact-Rational) (Option Exact-Rational) .... -> Renderer3d))] I agree with you that this is insane, and that Sam or Vincent should do something about it. :D In the meantime, write a new macro to use instead of `require/typed/provide'. (Macros inside types won't expand.) Fortunately, function types with keyword arguments already expand to `case->' types, so you don't have to change anything about those. Neil ⊥ _________________________ Racket Developers list: <a href="http://lists.racket-lang.org/dev" target="_blank">http://lists.racket-lang.org/dev</a> </blockquote></div> </div>