[Haskell-cafe] Re: If the local variable can be changed ...
John Lato
jwlato at gmail.com
Wed Mar 10 06:21:55 EST 2010
> From: zaxis <z_axis at 163.com>
>
> So if the local variable can be changed, then we can use loop, etc. same as
> imperative languages. For example, for (i=0; i<100; i++) where `i` is a
> local variable in function.
>
In addition to John Millikin's suggestion, you can also do:
map f [0..99]
where f :: Int -> a; f = ...
or
mapM f [0..99]
where f :: Int -> m a; f = ...
for monadic actions. Here "f" is the body of the loop. The loop
bodies must be completely independent, but this is a very useful
technique.
Cheers,
John
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