I think they need to be bigger, but case does have some smarts. Try
this one (add a `pretty-write` if you're running in cmd-line racket).
#lang racket
(syntax->datum
(expand
#'(case x
[(1 2 3 4 5 6 7 8 9 10) 1]
[(a b c d e f g h i j k l m n o p q r s t) 2])))
On Fri, Jun 3, 2016 at 6:23 PM, Gustavo Massaccesi <gust...@oma.org.ar> wrote:
> > [...] I saw in the docs that case specifically mentions it can
> distribute in log(n) time [...]
>
> I think it's strange. I found the reference in
> https://docs.racket-lang.org/reference/case.html but it's very
> strange. Is it true???
>
> For example, I tried with
>
> ;---
> #lang racket
> (lambda (x)
> (case x
> [(1 "1" #"1" |1|) 1]
> [(2 "2" #"2" |2|) 2]))
> (lambda (x)
> (case x
> [(1 3 5 7) 1]
> [(2 4 6 8) 2]))
> ;---
>
> but both expand to a bunch of nested if, nothing fancy that may run in
> O(log(N)).
> (I don't expect that it has a smarter implementation for bigger N.)
>
> Gustavo
>
>
> On Fri, Jun 3, 2016 at 11:40 AM, Gerald Pipes
> <gerald_pi...@student.uml.edu> wrote:
>> On Friday, June 3, 2016 at 10:30:35 AM UTC-4, Jon Zeppieri wrote:
>>> There's rarely a good reason. If you were dispatching over a very large set
>>> of constants -- fixnums or characters, in particular -- I'd expect better
>>> performance from case. That's about it.
>>>
>>> > On Jun 3, 2016, at 10:10 AM, Gerald Pipes <gerald_pi...@student.uml.edu>
>>> > wrote:
>>> >
>>> > I have been recently using match a lot and I was wondering what was the
>>> > main benefit of using case instead of match? It seems as though match
>>> > has the distribution on a single val-exp except match allows for the
>>> > pattern matching and case just uses equal?.
>>> >
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>>
>> Yes, I saw in the docs that case specifically mentions it can distribute in
>> log(n) time but for match there is no time mentioned. I assumed case's
>> performance was better because of the performance omission of match. Does
>> anyone know the actual performance of match?
>>
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>
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