[Haskell-cafe] I Need a Better Functional Language!

[Gábor Lehel]

On Thu, Apr 5, 2012 at 8:59 PM, Tillmann Rendel
<rendel at informatik.uni-marburg.de> wrote:
> Paul R wrote:
>>
>> I am curious what are interesting use-cases for that? Symbolic
>> analysis? self-compilers?
>
>
> Optimization. For example, imagine the following definition of function
> composition:
>
>  map f . map g = map (f . g)
>  f . g = \x -> f (g x)
>
> In Haskell, we cannot write this, because we cannot pattern match on
> function calls.
>
>  Tillmann

On the one hand, yes we can, with RULES:
http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/rewrite-rules.html

On the other hand, I've never used it, but this sounds a bit like Pure:
http://code.google.com/p/pure-lang/