Known Haskell Extensions

Links

• Please see the explanation and template for writing descriptions of these extensions.
•  Cabal extension list
•  GHC extension related options
• [source:/ExtensionTables.hs Script] to generate the original tables
•  GHC survey results (including a large list of Haskell extensions)

Support Matrix

Extension Name	GHC	NHC	HUGS	JHC
ForeignFunctionInterface	True	True	True
RecursiveDo	True	False	True
ParallelListComp	True	False	True
ScopedTypeVariables	True	False	True
PolymorphicComponents	True	False	True
Rank2Types	True	False	True
RankNTypes	True	False	False
ExistentialQuantification	True	True	True
ImplicitParams	True	False	True
EmptyDataDecls	True	True	True
NoMonomorphismRestriction	True	True	False
FlexibleContexts	True	False	True
FlexibleInstances	True	False	True
TypeSynonymInstances	True	False	True
MultiParamTypeClasses	True	False	True
OverlappingInstances	True	False	True
IncoherentInstances	True	False	True
UndecidableInstances	True	False	False
FunctionalDependencies	True	False	True
CPP?	True	True	True
TemplateHaskell?	True	False	False
InlinePhase?	True	False	False
ContextStack?	True	False	False
Arrows	True	False	False
Generics?	True	False	False
NoImplicitPrelude?	True	False	False
NamedFieldPuns?	False	True	False
ExtensibleRecords?	False	False	True
RestrictedTypeSynonyms?	False	False	True
HereDocuments?	False	False	True

Extensions supported by two compilers

• ForeignFunctionInterface
• RecursiveDo
• ParallelListComp
• ScopedTypeVariables
• PolymorphicComponents
• Rank2Types
• ExistentialQuantification
• ImplicitParams
• EmptyDataDecls
• NoMonomorphismRestriction
• FlexibleContexts
• FlexibleInstances
• TypeSynonymInstances
• MultiParamTypeClasses
• OverlappingInstances
• IncoherentInstances
• FunctionalDependencies
• CPP