Am Dienstag, 21. März 2006 11:28 schrieb Bulat Ziganshin:
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as i said, shebang patterns allow only to specify that IMPLEMENTATION of some function is strict. this helps only when this function are called directly. they can't help when function is passed as parameter or enclosed in data structure or a part of class. the same about datatypes - i can't declare what some algorithm works only with strict lists. i try to find extensions what will allow to specify strictness in every case where now we forced to use lazy computations
the concrete syntax what i propose may be wrong
Well, it's probably nice sometimes to have types which guarantee the strictness of certain components. For example, it might be good to have a list type where the strictness of the elements is guaranteed. But I'm sure that it's wrong to try to achieve this by annotating type arguments like in [!a]. I think, this approach is wrong, not just the syntax. Best wishes, Wolfgang
Hello Wolfgang, Wednesday, March 22, 2006, 1:29:24 AM, you wrote: you said WHAT you think but not said WHY? my motivation is to be able to use myriads of already implemented algorithms on new datatypes
as i said, shebang patterns allow only to specify that IMPLEMENTATION of some function is strict. this helps only when this function are called directly. they can't help when function is passed as parameter or enclosed in data structure or a part of class. the same about datatypes - i can't declare what some algorithm works only with strict lists. i try to find extensions what will allow to specify strictness in every case where now we forced to use lazy computations
the concrete syntax what i propose may be wrong
WJ> Well, it's probably nice sometimes to have types which guarantee the WJ> strictness of certain components. For example, it might be good to have a WJ> list type where the strictness of the elements is guaranteed. But I'm sure WJ> that it's wrong to try to achieve this by annotating type arguments like in WJ> [!a]. I think, this approach is wrong, not just the syntax. WJ> Best wishes, WJ> Wolfgang WJ> _______________________________________________ WJ> Haskell-prime mailing list WJ> Haskell-prime@haskell.org WJ> http://haskell.org/mailman/listinfo/haskell-prime -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com
Am Mittwoch, 22. März 2006 14:19 schrieb Bulat Ziganshin:
Hello Wolfgang,
you said WHAT you think but not said WHY? my motivation is to be able to use myriads of already implemented algorithms on new datatypes
I think, I already tried to explain why I think the way I think in an earlier mail:
Strictness has to refer to attributes (the things you apply a data constructor to). In you approach, strictness is connected to type arguments. This causes problems. For example, if you have
data T a = C a a,
what would T !a mean? Would both attributes be strict? But how would you force only one attribute to be strict then?
By the way, would it be okay for you to answer below the quotation, not above it? And would it be possible to use just a > sign, followed by a space for marking quotations. My MUA gets confused by things like “WJ> ”. Thank you very much.
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Best wishes, Wolfgang
participants (2)
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Bulat Ziganshin -
Wolfgang Jeltsch