!!! I have been notified that the Haskell language significantly changed from the time the first version of this reference has been published (especially system of modules). I am working on an update!!!
Haskell is a very nice functional language. While I have not been using it much recently, a lot of my Python and XSLT skills are derived from my playing with Haskell.
The reference is based on Haskell 98 Report and Haskell 98 Libraries Report
and a substantial part of descriptions comes from these specifications. The report excerpt:
Haskell is a general purpose, purely functional programming language incorporating many recent innovations in programming language design. Haskell provides higher-order functions, non-strict semantics, static polymorphic typing, user-defined algebraic datatypes, pattern-matching, list comprehensions, a module system, a monadic I/O system, and a rich set of primitive datatypes, including lists, arrays, arbitrary and fixed precision integers, and floating-point numbers. Haskell is both the culmination and solidification of many years of research on non-strict functional languages.
Prepared by: Miloslav Nic (Mila)