--- Abigail wrote:

Hi,

I would like to ask about what are tha main features of functional programming?

Caveat: I'm a relative newcomer to functional programming myself, certainly not an expert. There's the obvious definition: Functional programming is writing programs in the form of functions that are evaluated, as opposed to procedures that are evaluated. but even if it's tecnically correct, I'm not that such a distinction helps very much. I know it uses Scheme (a variety of Lisp) rather than Haskell, but ch. 3 of "The Structure and Interpretation of Programming Languages" (SICP) has a nice treatment of mutable data structures on the one hand, and delayed evaluation on the other. It's interesting because it gives some insight into the complementary nature of the approach taken by pure languages like Haskell (called streams in SICP), and non-functional techniques such as assignment. I like to think of this as a kind of time/space duality. If you think about the sequence of "events" during a computation, then you are squarely on the side of time, and your computational model is decidely imperative. If you're willing to let go a bit of time, and instead start thinking about comprehensions and (potentially) infinite lists, then you've moved over into the space camp, and your programming style becomes more functional. === Gregory Woodhouse "All truth passes through three stages: First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident." --Arthur Schopenhauer