Also if you're going to memoize things, why are you using assoc rather than a hash table? Or if at all possible, a weak hash table?
Carl Eastlund On Thu, Jun 6, 2013 at 6:35 PM, Robby Findler <ro...@eecs.northwestern.edu>wrote: > Can't we do better than a memo table? > > > On Thursday, June 6, 2013, wrote: > >> stamourv has updated `master' from 5ea3a1ce6d to 6e8c9ed15a. >> http://git.racket-lang.org/plt/5ea3a1ce6d..6e8c9ed15a >> >> =====[ 2 Commits ]====================================================== >> Directory summary: >> 82.9% collects/racket/contract/private/ >> 17.0% collects/scribblings/reference/ >> >> ~~~~~~~~~~ >> >> d1df869 Vincent St-Amour <stamo...@racket-lang.org> 2013-06-06 18:02 >> : >> | Document procedure-closure-contents-eq?. >> : >> M collects/scribblings/reference/procedures.scrbl | 5 +++++ >> >> ~~~~~~~~~~ >> >> 6e8c9ed Vincent St-Amour <stamo...@racket-lang.org> 2013-06-06 18:31 >> : >> | Memoize wrapped case-> range contracts. >> | >> | Fixes failing contract tests. >> : >> M collects/racket/contract/private/arrow.rkt | 21 +++++++++++++++------ >> >> =====[ Overall Diff ]=================================================== >> >> collects/racket/contract/private/arrow.rkt >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> --- OLD/collects/racket/contract/private/arrow.rkt >> +++ NEW/collects/racket/contract/private/arrow.rkt >> @@ -1712,12 +1712,21 @@ v4 todo: >> "the domain of" >> #:swap? #t))) >> dom-ctcs+case-nums) >> - (map (λ (f) >> - (define p (f rng-blame)) >> - (lambda args >> - (with-continuation-mark >> - contract-continuation-mark-key >> blame >> - (apply p args)))) >> + (map (let ([memo '()]) >> + ;; to preserve >> procedure-closure-contents-eq?ness of the >> + ;; wrapped procedures, memoize with f >> as the key. >> + (λ (f) >> + (define target >> + (assoc f memo >> procedure-closure-contents-eq?)) >> + (if target >> + (cdr target) >> + (let* ([p (f rng-blame)] >> + [new (lambda args >> + >> (with-continuation-mark >> + >> contract-continuation-mark-key blame >> + (apply p >> args)))]) >> + (set! memo (cons (cons f new) >> memo)) >> + new)))) >> rng-ctcs))) >> (define (chk val mtd?) >> (cond >> >> collects/scribblings/reference/procedures.scrbl >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> --- OLD/collects/scribblings/reference/procedures.scrbl >> +++ NEW/collects/scribblings/reference/procedures.scrbl >> @@ -88,6 +88,11 @@ to the wrong number of arguments, the resulting error >> hides the first >> argument as if the procedure had been compiled with the >> @indexed-racket['method-arity-error] syntax property.} >> >> +@defproc[(procedure-closure-contents-eq? [proc1 procedure?] >> + [proc2 procedure?]) boolean?]{ >> +Compares the contents of the closures of @racket[proc1] and >> @racket[proc2] >> +for equality by comparing closure elements pointwise using @racket[eq?]} >> + >> @; ---------------------------------------- >> @section{Keywords and Arity} >> >> > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev > >
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