Known Haskell Extensions

Links

• Please see the explanation and template for writing descriptions of these extensions.
• ExtensionsExperiment is a summary of experiments run on the hackage libraries.
•  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)
•  Results of John Hughes' Haskell survey (also lists many extensions)

Support Matrix

Extension Name	GHC	NHC	HUGS	JHC	Tickets
AssociatedTypes	False	False	False	False	#14, #90
ClassAliases?	False	False	False	False	No results
CoinductiveDictionaries?	?	False	False	False	No results
ContextStack?	True	False	False	False	No results
DataKinds?	False	False	False	False	No results
DoAndIfThenElse	False	False	False	False	#23
DottedHierarchicalModules	False	False	False	True	No results
EmptyDataDecls	True	True	True	True	#25
ExistentialQuantification	True	True	True	False	#26
ExplicitDictionaries?	False	False	False	False	No results
ExtensibleRecords?	False	False	True	False	No results
FlexibleContexts	True	False	True	?	#31
FlexibleInstances	True	False	True	?	#32
ForeignData	False	False	False	True	#34
ForeignFunctionInterface	True	True	True	True	#35
FunctionalDependencies	True	False	True	False	#36, #90
HereDocuments?	False	False	True	False	No results
HierarchicalModules	True	True	True	True	#24
ImplicitParams	True	False	True	False	#38
IncoherentInstances	True	False	True	False	#40, #54
InfixTypeConstructors	True	False	False	True	#78
InlinePhase?	True	False	False	False	No results
KindAnnotations	True	False	False	True	#84
KindPolymorphism?	False	False	False	False	No results
LambdaCase	False	False	False	False	#41
LiberalTypeSynonyms	True	False	False	True	#102
LinearImplicitParams	True	False	False	False	#43
MagicUnderscore	False	False	False	True	#44
MultiParamTypeClasses	True	False	True	False	#49, #90
MultiWayIf	False	False	False	False	#41, #77
NamedFieldPuns?	False	True	False	False	#136
NewtypeDeriving	True	False	False	True	#22, #52
NoImplicitPrelude?	True	False	False	True	No results
NoMonomorphismRestriction	True	True	False	True	#131 #80, #131
NondecreasingIndentation	True	?	True	?	#53
OverlappingInstances	True	False	True	False	#54
ParallelListComp	True	False	True	False	#55
PartialTypeSigs	False	False	False	False	#40
PatternGuards	True	False	False	False	#56
PolymorphicComponents	True	False	True	False	#57
RebindableSyntax?	True	False	False	Some	No results
RecursiveDo	True	False	True	False	#64
RecursiveModules?	Partial	Partial	False	True	No results
RestrictedTypeSynonyms?	False	False	True	False	No results
RewriteRules?	True	False	False	Int	No results
ScopedTypeVariables	True	False	True	False	#67, #81
TemplateHaskell?	True	False	False	False	No results
TypeSynonymInstances	True	False	True	True	#70
UnboxedTypes?	True	False	False	Int	No results
UndecidableInstances	True	False	False	False	#71
Views	False	False	False	False	#73, #114
Arrows	True	False	False	False	#13
Assertions?	True	?	False	True	#107
Concurrency	True	False	Coop	Poor	#74
CPP?	True	True	True	True	No results
GADTs	True	False	False	False	#37
Generics?	True	False	False	False	#88
Impredicativity?	?	False	False	False	#87
Rank2Types	True	False	True	False	#60
RankNTypes	True	False	False	False	#60
AllowImportAnywhere	False	False	False	False	#82

Extensions supported by two compilers

• HierarchicalModules
• ForeignFunctionInterface
• RecursiveDo
• ParallelListComp
• ScopedTypeVariables
• PolymorphicComponents
• Rank2Types
• ExistentialQuantification
• ImplicitParams
• EmptyDataDecls
• NoMonomorphismRestriction
• NondecreasingIndentation
• FlexibleContexts
• FlexibleInstances
• TypeSynonymInstances
• MultiParamTypeClasses
• OverlappingInstances
• IncoherentInstances
• FunctionalDependencies
• CPP
•  O'Haskell

Extensions used in fptools

Those mentioned in library .cabal files
CPP	11 libraries
ForeignFunctionInterface	4
MultiParamTypeClasses	3
OverlappingInstances	1
FunctionalDependencies	1
Additional extensions mentioned in source file "Portability" field
Concurrency	3 libraries
Local universal quantification	3
Extended exceptions	>1
Existentially quantified data constructors	1
STM	1