[Haskell-cafe] Question on leazy evaluation

[Pierre Barbier de Reuille]

Henning Thielemann a écrit :
> On Thu, 24 Mar 2005, Pierre Barbier de Reuille wrote:
> 
> 
>>My question is: is there some (simple?) rule/criteria to ensure leazy
>>evaluation will be efficient ?
> 
> 
>  One rule of thumb is: If your implementation works for infinite lists
> then it will also be quite efficient for finite lists.
>  Do you mean criteria of this kind?
> 

I think you mean doing something like :

take 10 (fct infiniteList)

.. this answers my first question: how to be sure it uses leazy 
evaluation :). But now the second (hardest ?) question: if the answer is 
"no", how can I detect where leazy evaluation fails ? Is there first 
approximation rules, at least pointing where leazy evaluation is likely 
to fail ? (like avoiding functions like length, minimum, ..., some 
structure ...)

Pierre

-- 
Pierre Barbier de Reuille

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