I think maybe signals a well-known functional idea.
On May 8, 2014, at 8:03 PM, Robby Findler wrote: > (or/c #f x) > > seems better than maybe/c because it is nearly the same length and it > is one less thing to memorize (and it's not like single-point of > control applies here because this can never change). > > Robby > > On Thu, May 8, 2014 at 6:17 PM, Matthias Felleisen <matth...@ccs.neu.edu> > wrote: >> >> (We have maybe/c somewhere, and I think we should use it.) >> >> >> On May 8, 2014, at 4:19 PM, sa...@racket-lang.org wrote: >> >>> samth has updated `master' from 98ae3d8b2d to e1ab2ffcf4. >>> http://git.racket-lang.org/plt/98ae3d8b2d..e1ab2ffcf4 >>> >>> =====[ One Commit ]===================================================== >>> Directory summary: >>> 100.0% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/ >>> >>> ~~~~~~~~~~ >>> >>> e1ab2ff Sam Tobin-Hochstadt <sa...@cs.indiana.edu> 2014-05-08 16:18 >>> : >>> | Fix contract. >>> | >>> | First bug caught with new test. Thanks Robby! >>> : >>> M .../typed-racket-lib/typed-racket/infer/infer-unit.rkt | 2 +- >>> >>> =====[ Overall Diff ]=================================================== >>> >>> pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt >>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> --- >>> OLD/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt >>> +++ >>> NEW/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt >>> @@ -360,7 +360,7 @@ >>> (Type/c Type/c . -> . (or/c #f cset?)) >>> (cgen V X Y S T)) >>> (define/cond-contract (cg/inv S T) >>> - (Type/c Type/c . -> . cset?) >>> + (Type/c Type/c . -> . (or/c #f cset?)) >>> (cgen/inv V X Y S T)) >>> ;; this places no constraints on any variables in X >>> (define empty (empty-cset X Y)) >> >> >> _________________________ >> Racket Developers list: >> http://lists.racket-lang.org/dev _________________________ Racket Developers list: http://lists.racket-lang.org/dev