FWIW, arguments in Racket are always passed on a stack. Robby
On Sun, Jan 8, 2012 at 9:12 PM, Gregory Woodhouse <gregwoodho...@me.com> wrote: > I suppose it could prevent certain optimizations in parameter passing, > forcing space for arguments to be allocated on the heap. > > Sent from my iPad > > On Jan 8, 2012, at 12:42 PM, Danny Yoo <d...@cs.wpi.edu> wrote: > >> On Sun, Jan 8, 2012 at 3:23 PM, Jordan Schatz <jor...@noionlabs.com> wrote: >>> This code runs, but I'm guessing that its not the "right way" to do it. >>> >>> (define (js-date [i (current-date)]) >>> (let ([original-format (date-display-format)] >>> [return ((λ () >>> (date-display-format 'rfc2822) >>> (date->string i #t)))]) >>> (date-display-format original-format) >>> return)) >>> >>> 1) In "some other language" using a function as the default value for an >>> argument is inefficient and frowned upon. Is that the case in racket? >> >> Hi Jordan, >> >> Can you give an example of such a language? I'm curious. >> >> I'm not sure where the inefficiency would come from, unless computing >> the default value expression's value is costly. >> >> According to the documentation in: >> >> http://docs.racket-lang.org/reference/lambda.html#(form._((lib._racket/private/base..rkt)._lambda)) >> >> with regards to "default-expr": "... if no such argument is provided, >> the default-expr is evaluated to produce a value associated with id." >> >> From the reference docs, it sounds like that, unlike a language like >> Python, the default value is evaluated for every use of the function, >> rather than just once when the function's defined. We can experiment >> with this: > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
