<div dir="ltr"><div>Asumu, </div>Not sure I follow. If one uses a typed function imported into untyped Racket all bets are off. (module foo typed/racket (provide double) (: double (Integer -> Integer)) (define (double x) (+ x x))) (module bar racket (require 'foo) (double "2")) (require 'bar) ;; fails </div><div class="gmail_extra"> <div class="gmail_quote"> On Mon, May 6, 2013 at 10:27 AM, Asumu Takikawa <<a href="mailto:asumu@ccs.neu.edu" target="_blank">asumu@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="im">On 2013-05-06 10:09:06 -0400, Ray Racine wrote: > The below is now failing for me. > (struct: Stuff ([this : String][that : Natural]) #:prefab) > </div>> [...] <div class="im">> > If there is a typing issue with the use of #:prefab and its banishment > permanent, is there an alternate best practice mechanism for easy struct: > serialization/de-serialization? </div>If you're using the Racket pre-release, then that was probably my commit that broke that. Sorry for breaking compatibility here, but it's unsound for TR to admit #:prefab as is. Here's an example: $ racket Welcome to Racket v5.3. -> (module foo typed/racket (struct: foo ([f : (Float -> Float)]) #:prefab) (define x (foo (lambda: ([x : Float]) (* 3.3 x)))) (provide x)) -> (module bar racket (require 'foo) (struct foo (f) #:prefab) ((foo-f x) "foo")) -> (require 'bar) 2.293305645053357e-309 The first module exports a #:prefab struct instance containing an optimized (Float -> Float) function. Since it's a prefab, the second module (which is untyped), can freely access the function stored inside. Since the function is unprotected, it does an unsafe multiplication on a string and no contract error is raised. I'm not sure what's a good alternative for serialization in TR off the top of my head. Cheers, Asumu </blockquote></div> </div>