On 12/20/05, Daniel Carrera
Hi all,
I've finished a first draft of what I call "First steps in Haskell". It's intended to be the very first thing a new user sees when they decide to try out Haskell.
http://www.haskell.org/hawiki/FirstSteps?action=show
It's a bit longer than I'd like, but I don't inmediately see anything I can take out without losing something valuable (given the purpose of this document).
Thoughts and comments?
It looks very good. The length isn't a problem to me, if anything I'd be happy expanding a little. One thing I'd consider adding is something along the lines of a section: ------------------------------------------------------------------------------------ == So how do I write "Hello, world"? == Well, the first thing you need to understand that in a functional language like Haskell, this is a harder question than it seems. Most of the code you will write in Haskell is "purely functional", which means that it returns the same thing every time it is run, and has no side effects. Code with side effects is referred to as "imperative", and is carefully isolated from functional code in Haskell. To deal with the distinction between functional and imperative code, Haskell uses a construct called the "IO monad". It's not hard to understand - basically, it's just a way of "wrapping up" imperative code so that there's a clear boundary between it and functional code - but most tutorial presentations of Haskell start with functional code, and introduce the IO monad later. As a taster, though, here is "Hello, world" in Haskell: {{{ module Main where main :: IO () main = putStrLn "Hello, World!" }}} Put this in a file called hello.hs, and compile it with `ghc -make hello.hs -o hello`. You'll get an executable called hello (or hello.exe on Windows). Run it to see the output. There will be plenty more on writing standalone programs, IO, and other aspects of the IO monad, as you learn more about Haskell. ------------------------------------------------------------------------------------ The point is, people *will* want to write "hello, world", so don't put them off by making it seem "hard". Show them how, explain where they will find out more, and explain why things like this come naturally at a later stage when learning Haskell than they do with, say, C. Paul.