[Haskell-cafe] Re: Why Haskell?

[Brian Hulley]

Simon Marlow wrote:
> Neil Mitchell wrote:
>
>> Would it not be possible to add a GHC rule like the following:
>>
>> forall a b . sequence a >> b  = sequence_ a >> b
>>
>> I'm not sure if thats correct, a valid rule definition, or semantics
>> preserving, but if it was it would be nice :)
>
> Now there's a good idea!

Well this would work in the case of sequence vs sequence_ but it seems to me 
that what's really needed is a compiler that can do whole program 
optimization so that the list building inside sequence would be eliminated 
in this case (because the list is never used) without needing an ad-hoc 
re-write rule. Otherwise, a programmer must know about all the re-write 
rules as well as all the functions, and be able to apply them in their head 
to calculate what the space/time complexity of their program actually is, 
which imho is much more difficult than just writing sequence_ in the first 
place.

Has anyone done work on an equivalent of MLton for Haskell?

Thanks, Brian.
-- 
Logic empowers us and Love gives us purpose.
Yet still phantoms restless for eras long past,
congealed in the present in unthought forms,
strive mightily unseen to destroy us.

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