Hello, I am interested in using global variables (in GHC). I need a variable to store list of Integers to store temporary results. I have been reading the module MVar, but I wonder if there is an alternative way of doing it. I have already implemented my function using an auxiliar argument where I put my lists of Integers. Will the use of a global variable improve my function?

There's many ways to achieve the same goals as C programmers achieve using mutable (global) variables including using laziness, use of "accumulator" arguments, and, supported by most compilers but not standard Haskell, mutable variables. (Unlearning imperative programming habits is one of the big challenges in learning Haskell.) Since there are so many ways to avoid mutable variables and (many less) circumstances where mutable variables are the best solution, it's hard to give useful advice without more information about the problem. -- Alastair Reid reid@cs.utah.edu http://www.cs.utah.edu/~reid/