Haskell Language Common GHC Language Extensions
Remarks
These language extensions are typically available when using the Glasgow Haskell Compiler (GHC) as they are not part of the approved Haskell 2010 language Report. To use these extensions, one must either inform the compiler using a flag or place a LANGUAGE programa before the module keyword in a file. The official documentation can be found in section 7 of the GCH users guide.
The format of the LANGUAGE programa is {-# LANGUAGE ExtensionOne, ExtensionTwo ... #-}. That is the literal {-# followed by LANGUAGE followed by a comma separated list of extensions, and finally the closing #-}. Multiple LANGUAGE programas may be placed in one file.
