global variable

Jon Fairbairn Jon.Fairbairn at
Sun Oct 12 22:59:56 EDT 2003

On 2003-10-12 at 21:23BST Jose Morais wrote:
> Sorry the newbie question and the insistence, but how exactly do I use
> map or fold applied to the infinite list to get successive integers at
> each time?

You don't. The infinite list /is/ all the successive integers.

I think at this point it would be useful if you could say
what you are trying to do -- what programme are you trying
to write, as opposed to what imperative-sounding programming
technique you are trying to duplicate.

For example, where in an imperative language you might print
the first 10 squares by setting a variable to successive
integers, in Haskell you could write:

positive_naturals = [1..]
squares = map (^2) positive_naturals

main = print $ take 10 squares

which has a similar effect


Jón Fairbairn                                 Jon.Fairbairn at

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