[Haskell-cafe] Problems with strictness analysis?

David Menendez dave at zednenem.com
Mon Nov 3 17:45:19 EST 2008


On Mon, Nov 3, 2008 at 5:39 PM, Henning Thielemann
<lemming at henning-thielemann.de> wrote:
>
> On Mon, 3 Nov 2008, Luke Palmer wrote:
>
>> On Mon, Nov 3, 2008 at 2:54 PM, Don Stewart <dons at galois.com> wrote:
>>>
>>> "Optimisations" enable strictness analysis.
>>
>> I was actually being an annoying purist.  "f is strict" means "f _|_ =
>> _|_", so strictness is a semantic idea, not an operational one.
>> Optimizations can change operation, but must preserve semantics.
>>
>> But I'm not just picking a fight.  I'm trying to promote equational
>> reasoning over operational reasoning in the community, since I believe
>> that is Haskell's primary strength.
>
> Maybe I missed the point, but the optimization seems correct to me. Without
> optimization and its (strictness) analysis the program would still output
> the correct answer - given that the stack is sufficiently large.
> Optimization simply makes this program run using much less space. Right?

I think Luke was commenting on the terminology, not the optimization.
We have a tendency to say "lazy" when we mean "non-strict" and
"strict" when we mean "eager".

-- 
Dave Menendez <dave at zednenem.com>
<http://www.eyrie.org/~zednenem/>


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