Haskell

Haskell 2010 is an incremental update to the language, mostly incorporating several well-used and uncontroversial features previously enabled via compiler-specific flags.

A "Hello, World!" program in Haskell (only the last line is strictly necessary):

-- [[Type signature|Type annotation]] (optional, same for each implementation)

An implementation of an algorithm similar to quick sort over lists, where the first element is taken as the pivot:

Implementations that fully or nearly comply with the Haskell 98 standard, include:

Implementations not fully Haskell 98 compliant, and using a variant Haskell language, include:

A series of languages inspired by Haskell, but with different type systems, have been developed, including:

The Haskell community meets regularly for research and development activities. The main events are: