Hi,
For the reason that I'm lazy and don't want to have to modify all my functions which use afact, or call functions which use afact, and don't see why I should have to -- they were able to call the 'fact' function as a global, and can refer to a global 'afact' if I define it outside of main with a fixed value. I don't see why having a global dependent on outside input should be so much harder.
Of course afact depends on the value of n, which is only known in main. So you need a way of passing n to afact, and you get the same problem as before.
So perhaps you want to simulate a global variable.
Yeah. And I've tried various permutations
let afact = ... in let (glo, ...
let afact = ... in (glo, ...
let afact = ... in (glo, ...
let afact = ... let (glo...
None of these will work because of the scoping rules in Haskell (which are static, perhaps you are used to languages with dynamic scope?). If you follow the desugaring rules for do notation, it might be clearer how the scoping rules work. I posted a reference in my previous mail. So if you want a global variable - read the paper by Hughes that I mentioned previously. It is short, easy to understand, and covers the typical ways Haskell programmers might try to do it (dirty and clean). It might even clarify the scoping issues involved. If you can't be bothered to read the paper, then I'm afraid you'll have to thread the value of afact through your code. Cheers, Bernie.