I guess I was thinking that the functional language's compiler/interpreter would deal with spreading the work across the cores when appropriate. For example if

I guess I was thinking that the functional language's compiler/interpreter would deal with spreading the work across the cores when appropriate. For example if a billion item data structure is feed into some function, say a map that reformats a string, it would be sent to as many cores as were available to simultaneously process a portion of the data then recombine the results (kinda like how Hadoop works). Obviously this is not trivial but certainly seems easier than either doing this automatically in a language with side effects or manually programming the multi-core logic. None of the languages I've uses can do anything like this but I thought Haskell and some of the new generation of languages were headed that way.