Learning Haskell

Introduction

Haskell is a general purpose, purely functional programming language. This portal points to places where you can go if you want to learn Haskell.

The introduction on the Haskell homepage tells you that Haskell gives you: substantially increased programmer productivity; shorter, clearer, and more maintainable code; fewer errors; higher reliability; a smaller "semantic gap" between the programmer and the language; shorter lead times.

There is an old - but still relevant - paper about Why Functional Programming Matters by John Hughes. More recently Sebastian Sylvan started a web page on this topic.
And there is a table comparing Haskell to other functional languages.
Many questions about functional programming are answered by the comp.lang.functional FAQ.

Implementations
	Messages	Size	Tools	Remarks
Hugs	`+/-`	`++`	`-`	Fast compilation; used a lot for learning Haskell
GHC	`+`	`-`	`++`	Many language extensions; generated code very fast
NHC	`?`	`+`	`++`	Profiling; debugging; tracing
Helium	`++`	`++`	`-`	No type classes (yet!) and thus incompatible with most material on this site