So if code is using first/rest instead of car/cdr when I already know the lists are proper, it could incur a significant performance penalty? After all, memoization still needs a table lookup each time I do a first/rest.
(i.e. implementing datastructures in terms of lists should use car/cdr for performance right? any benchmarks?) On Friday, March 7, 2014, Sean Kanaley <skana...@gmail.com> wrote: > Pardon me, but going back a bit where the blog about switching to > immutable lists was mentioned...I saw an interesting comment about > immutability and eq?. Have any mathematicians come up with an answer for > the meaning of eq? on permanently distinct but equivalent and immutable > objects, e.g. (eq? (cons 3 2) (cons 3 2))? What about on immutable objects > that have mutable internal state, e.g. memoizing functions? > Naive-but-memoized (fib 1000) is not necessarily the same as (fib 1000), > unless the answer doesn't depend on the number of universes that have > bigbanged meanwhile. > > > > On Fri, Mar 7, 2014 at 2:31 PM, Daniel Carrera > <dcarr...@gmail.com<javascript:_e(%7B%7D,'cvml','dcarr...@gmail.com');> > > wrote: > >> Thanks. >> >> >> On 7 March 2014 20:22, Harry Spier >> <vasishtha.sp...@gmail.com<javascript:_e(%7B%7D,'cvml','vasishtha.sp...@gmail.com');> >> > wrote: >> >>> See also this previous thread on the Racket list. >>> http://www.mail-archive.com/users%40racket-lang.org/msg12161.html >>> >>> >>> >>> >>> ____________________ >>> Racket Users list: >>> http://lists.racket-lang.org/users >>> >>> >> >> >> -- >> When an engineer says that something can't be done, it's a code phrase >> that means it's not fun to do. >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users >> >> >
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