[Haskell-cafe] curious about sum

[Thomas Davie]

No, I think it's extremely useful.  It highlights that numbers can  
both be lazy and strict, and that the so called "useless" lazy sum, is  
in fact, useful.

Bob

On 18 Jun 2009, at 13:29, Keith Sheppard wrote:

> OK, I think I went off on a tangent that isn't very useful anyway
>
> thanks
> -Keith
>
> On Wed, Jun 17, 2009 at 6:32 PM, Lennart
> Augustsson<lennart at augustsson.net> wrote:
>> The creators of Haskell didn't pick any particular representation  
>> for numbers.
>> (Well, literals are kind of In..tegers.)  You can pick what types you
>> make instances of Num.
>> Some of them are lazy, some of them are strict.
>>
>> On Wed, Jun 17, 2009 at 11:05 PM, Keith  
>> Sheppard<keithshep at gmail.com> wrote:
>>> In lambda calculus numbers are just functions and you evaluate them
>>> just like any other function. Haskell could have chosen the same
>>> representation for numbers and all evaluation on numbers would be  
>>> lazy
>>> (assuming normal order evaluation). I think that would have been the
>>> "Purist Lazy" way to go. That is not the way the creators of Haskell
>>> designed language though... am i missing something?
>>>
>>> On Wed, Jun 17, 2009 at 4:05 PM, Lennart
>>> Augustsson<lennart at augustsson.net> wrote:
>>>> What do you mean by "literals are strict"?  Strictness is a  
>>>> semantic
>>>> property of functions, and while literals can be overloaded to be
>>>> functions I don't know what you mean.
>>>>
>>>> On Wed, Jun 17, 2009 at 9:50 PM, Keith  
>>>> Sheppard<keithshep at gmail.com> wrote:
>>>>> Haskell's numeric literals are strict. You wouldn't want that to
>>>>> change right? It seems to me that having sum and product be  
>>>>> strict is
>>>>> consistent with this.
>>>>>
>>>>> -Keith
>>>>>
>>>>> On Wed, Jun 17, 2009 at 11:15 AM, Thomas  
>>>>> Davie<tom.davie at gmail.com> wrote:
>>>>>>
>>>>>> On 17 Jun 2009, at 13:32, Yitzchak Gale wrote:
>>>>>>
>>>>>>> Henk-Jan van Tuyl wrote:
>>>>>>>>
>>>>>>>> reverse
>>>>>>>> maximum
>>>>>>>> minimum
>>>>>>>
>>>>>>> Oh yes, please fix those also!
>>>>>>
>>>>>> import Prelude.Strict?
>>>>>>
>>>>>> Honestly, these functions are ones that I've *deffinately* used  
>>>>>> lazy
>>>>>> versions of, in fact, in the cases of minimum/maximum I've even  
>>>>>> used ones
>>>>>> that are super-lazy and parallel using unamb.
>>>>>>
>>>>>> It would be extremely odd to randomly decide "most people would  
>>>>>> want this to
>>>>>> be strict" based on no knowledge of what they're actually  
>>>>>> doing.  Instead,
>>>>>> why don't we stand by the fact that haskell is a lazy language,  
>>>>>> and that the
>>>>>> functions we get by default are lazy, and then write a strict  
>>>>>> prelude as I
>>>>>> suggest above to complement the lazy version.
>>>>>>
>>>>>> Bob
>>>>>> _______________________________________________
>>>>>> Haskell-Cafe mailing list
>>>>>> Haskell-Cafe at haskell.org
>>>>>> http://www.haskell.org/mailman/listinfo/haskell-cafe
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> keithsheppard.name
>>>>> _______________________________________________
>>>>> Haskell-Cafe mailing list
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>>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> keithsheppard.name
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>>
>
>
>
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> keithsheppard.name
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