optimization of list comprehensions

Robert Virding robert.virding@REDACTED
Thu Mar 2 11:16:43 CET 2006

I have been thinking about this a bit and I wonder if the constructing 
of the return list really causes any problems. Space-wise it will only 
be as large as the size of the input list, so I wouldn't worry.


Ulf Wiger (AL/EAB) skrev:
> I've seen many examples of how people use
> list comprehensions as a form of beautified
> lists:foreach() - that is, they don't care
> about the return value of the comprehension.
> I hesitate to say that it's bad practice,
> even though one will build a potentially
> large list unnecessarily, since it's 
> actually looks a lot nicer than using 
> lists:foreach().
> Question: would it be in some way hideous
> to introduce an optimization where such
> list comprehensions do everything except
> actually build the list? Then they could
> execute in constant space.
> /Ulf W

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