Cabal-syntax-3.9.0.0: A library for working with .cabal files

Description

Synopsis

# Documentation

data Language Source #

This represents a Haskell language dialect.

Language Extensions are interpreted relative to one of these base languages.

Constructors

#### Instances

Instances details

List of known (supported) languages for GHC

data Extension Source #

This represents language extensions beyond a base Language definition (such as Haskell98) that are supported by some implementations, usually in some special mode.

Where applicable, references are given to an implementation's official documentation.

Constructors

 EnableExtension KnownExtension Enable a known extension DisableExtension KnownExtension Disable a known extension UnknownExtension String An unknown extension, identified by the name of its LANGUAGE pragma.

#### Instances

Instances details

Known Haskell language extensions, including deprecated and undocumented ones.

Check “Overview of all language extensions” in GHC User’s Guide for more information.

Constructors

 OverlappingInstances Allow overlapping class instances, provided there is a unique most specific instance for each use. UndecidableInstances Ignore structural rules guaranteeing the termination of class instance resolution. Termination is guaranteed by a fixed-depth recursion stack, and compilation may fail if this depth is exceeded. IncoherentInstances Implies OverlappingInstances. Allow the implementation to choose an instance even when it is possible that further instantiation of types will lead to a more specific instance being applicable. DoRec (deprecated) Deprecated in favour of RecursiveDo.Old description: Allow recursive bindings in do blocks, using the rec keyword. See also RecursiveDo. RecursiveDo Allow recursive bindings in do blocks, using the rec keyword, or mdo, a variant of do. ParallelListComp Provide syntax for writing list comprehensions which iterate over several lists together, like the zipWith family of functions. MultiParamTypeClasses Allow multiple parameters in a type class. MonomorphismRestriction Enable the dreaded monomorphism restriction. DeepSubsumption Enable deep subsumption, relaxing the simple subsumption rules, implicitly inserting eta-expansions when matching up function types with different quantification structures. FunctionalDependencies Allow a specification attached to a multi-parameter type class which indicates that some parameters are entirely determined by others. The implementation will check that this property holds for the declared instances, and will use this property to reduce ambiguity in instance resolution. Rank2Types (deprecated) A synonym for RankNTypes.Old description: Like RankNTypes but does not allow a higher-rank type to itself appear on the left of a function arrow. RankNTypes Allow a universally-quantified type to occur on the left of a function arrow. PolymorphicComponents (deprecated) A synonym for RankNTypes.Old description: Allow data constructors to have polymorphic arguments. Unlike RankNTypes, does not allow this for ordinary functions. ExistentialQuantification Allow existentially-quantified data constructors. ScopedTypeVariables Cause a type variable in a signature, which has an explicit forall quantifier, to scope over the definition of the accompanying value declaration. PatternSignatures Deprecated, use ScopedTypeVariables instead. ImplicitParams Enable implicit function parameters with dynamic scope. FlexibleContexts Relax some restrictions on the form of the context of a type signature. FlexibleInstances Relax some restrictions on the form of the context of an instance declaration. EmptyDataDecls Allow data type declarations with no constructors. CPP Run the C preprocessor on Haskell source code. KindSignatures Allow an explicit kind signature giving the kind of types over which a type variable ranges. BangPatterns Enable a form of pattern which forces evaluation before an attempted match, and a form of strict let/where binding. TypeSynonymInstances Allow type synonyms in instance heads. TemplateHaskell Enable Template Haskell, a system for compile-time metaprogramming. ForeignFunctionInterface Enable the Foreign Function Interface. In GHC, implements the standard Haskell 98 Foreign Function Interface Addendum, plus some GHC-specific extensions. Arrows Enable arrow notation. Generics (deprecated) Enable generic type classes, with default instances defined in terms of the algebraic structure of a type. ImplicitPrelude Enable the implicit importing of the module Prelude. When disabled, when desugaring certain built-in syntax into ordinary identifiers, use whatever is in scope rather than the Prelude -- version. NamedFieldPuns Enable syntax for implicitly binding local names corresponding to the field names of a record. Puns bind specific names, unlike RecordWildCards. PatternGuards Enable a form of guard which matches a pattern and binds variables. GeneralizedNewtypeDeriving Allow a type declared with newtype to use deriving for any class with an instance for the underlying type. GeneralisedNewtypeDeriving ExtensibleRecords Enable the "Trex" extensible records system. RestrictedTypeSynonyms Enable type synonyms which are transparent in some definitions and opaque elsewhere, as a way of implementing abstract datatypes. HereDocuments Enable an alternate syntax for string literals, with string templating. MagicHash Allow the character # as a postfix modifier on identifiers. Also enables literal syntax for unboxed values. TypeFamilies Allow data types and type synonyms which are indexed by types, i.e. ad-hoc polymorphism for types. StandaloneDeriving Allow a standalone declaration which invokes the type class deriving mechanism. UnicodeSyntax Allow certain Unicode characters to stand for certain ASCII character sequences, e.g. keywords and punctuation. UnliftedFFITypes Allow the use of unboxed types as foreign types, e.g. in foreign import and foreign export. InterruptibleFFI Enable interruptible FFI. CApiFFI Allow use of CAPI FFI calling convention (foreign import capi). LiberalTypeSynonyms Defer validity checking of types until after expanding type synonyms, relaxing the constraints on how synonyms may be used. TypeOperators Allow the name of a type constructor, type class, or type variable to be an infix operator. RecordWildCards Enable syntax for implicitly binding local names corresponding to the field names of a record. A wildcard binds all unmentioned names, unlike NamedFieldPuns. RecordPuns Deprecated, use NamedFieldPuns instead. DisambiguateRecordFields Allow a record field name to be disambiguated by the type of the record it's in. TraditionalRecordSyntax Enable traditional record syntax (as supported by Haskell 98) OverloadedStrings Enable overloading of string literals using a type class, much like integer literals. GADTs Enable generalized algebraic data types, in which type variables may be instantiated on a per-constructor basis. Implies GADTSyntax. GADTSyntax Enable GADT syntax for declaring ordinary algebraic datatypes. MonoPatBinds (deprecated) Has no effect.Old description: Make pattern bindings monomorphic. RelaxedPolyRec Relax the requirements on mutually-recursive polymorphic functions. ExtendedDefaultRules Allow default instantiation of polymorphic types in more situations. UnboxedTuples Enable unboxed tuples. DeriveDataTypeable Enable deriving for classes Typeable and Data. DeriveGeneric Enable deriving for Generic and Generic1. DefaultSignatures Enable support for default signatures. InstanceSigs Allow type signatures to be specified in instance declarations. ConstrainedClassMethods Allow a class method's type to place additional constraints on a class type variable. PackageImports Allow imports to be qualified by the package name the module is intended to be imported from, e.g.import "network" Network.Socket ImpredicativeTypes (deprecated) Allow a type variable to be instantiated at a polymorphic type. NewQualifiedOperators (deprecated) Change the syntax for qualified infix operators. PostfixOperators Relax the interpretation of left operator sections to allow unary postfix operators. QuasiQuotes Enable quasi-quotation, a mechanism for defining new concrete syntax for expressions and patterns. TransformListComp Enable generalized list comprehensions, supporting operations such as sorting and grouping. MonadComprehensions Enable monad comprehensions, which generalise the list comprehension syntax to work for any monad. ViewPatterns Enable view patterns, which match a value by applying a function and matching on the result. XmlSyntax Allow concrete XML syntax to be used in expressions and patterns, as per the Haskell Server Pages extension language: http://www.haskell.org/haskellwiki/HSP. The ideas behind it are discussed in the paper "Haskell Server Pages through Dynamic Loading" by Niklas Broberg, from Haskell Workshop '05. RegularPatterns Allow regular pattern matching over lists, as discussed in the paper "Regular Expression Patterns" by Niklas Broberg, Andreas Farre and Josef Svenningsson, from ICFP '04. TupleSections Enable the use of tuple sections, e.g. (, True) desugars into x -> (x, True). GHCForeignImportPrim Allow GHC primops, written in C--, to be imported into a Haskell file. NPlusKPatterns Support for patterns of the form n + k, where k is an integer literal. DoAndIfThenElse Improve the layout rule when if expressions are used in a do block. MultiWayIf Enable support for multi-way if-expressions. LambdaCase Enable support lambda-case expressions. RebindableSyntax Makes much of the Haskell sugar be desugared into calls to the function with a particular name that is in scope. ExplicitForAll Make forall a keyword in types, which can be used to give the generalisation explicitly. DatatypeContexts Allow contexts to be put on datatypes, e.g. the Eq a in data Eq a => Set a = NilSet | ConsSet a (Set a). MonoLocalBinds Local (let and where) bindings are monomorphic. DeriveFunctor Enable deriving for the Functor class. DeriveTraversable Enable deriving for the Traversable class. DeriveFoldable Enable deriving for the Foldable class. NondecreasingIndentation Enable non-decreasing indentation for do blocks. SafeImports Allow imports to be qualified with a safe keyword that requires the imported module be trusted as according to the Safe Haskell definition of trust.import safe Network.Socket Safe Compile a module in the Safe, Safe Haskell mode -- a restricted form of the Haskell language to ensure type safety. Trustworthy Compile a module in the Trustworthy, Safe Haskell mode -- no restrictions apply but the module is marked as trusted as long as the package the module resides in is trusted. Unsafe Compile a module in the Unsafe, Safe Haskell mode so that modules compiled using Safe, Safe Haskell mode can't import it. ConstraintKinds Allow type classimplicit parameterequality constraints to be used as types with the special kind constraint. Also generalise the (ctxt => ty) syntax so that any type of kind constraint can occur before the arrow. PolyKinds Enable kind polymorphism. DataKinds Enable datatype promotion. TypeData Enable type data declarations, defining constructors at the type level. ParallelArrays Enable parallel arrays syntax ([:, :]) for Data Parallel Haskell. RoleAnnotations Enable explicit role annotations, like in (type role Foo representational representational). OverloadedLists Enable overloading of list literals, arithmetic sequences and list patterns using the IsList type class. EmptyCase Enable case expressions that have no alternatives. Also applies to lambda-case expressions if they are enabled. AutoDeriveTypeable (deprecated) Deprecated in favour of DeriveDataTypeable.Old description: Triggers the generation of derived Typeable instances for every datatype and type class declaration. NegativeLiterals Desugars negative literals directly (without using negate). BinaryLiterals Allow the use of binary integer literal syntax (e.g. 0b11001001 to denote 201). NumDecimals Allow the use of floating literal syntax for all instances of Num, including Int and Integer. NullaryTypeClasses Enable support for type classes with no type parameter. ExplicitNamespaces Enable explicit namespaces in module import/export lists. AllowAmbiguousTypes Allow the user to write ambiguous types, and the type inference engine to infer them. JavaScriptFFI Enable foreign import javascript. PatternSynonyms Allow giving names to and abstracting over patterns. PartialTypeSignatures Allow anonymous placeholders (underscore) inside type signatures. The type inference engine will generate a message describing the type inferred at the hole's location. NamedWildCards Allow named placeholders written with a leading underscore inside type signatures. Wildcards with the same name unify to the same type. DeriveAnyClass Enable deriving for any class. DeriveLift Enable deriving for the Lift class. StaticPointers Enable support for 'static pointers' (and the static keyword) to refer to globally stable names, even across different programs. StrictData Switches data type declarations to be strict by default (as if they had a bang using BangPatterns), and allow opt-in field laziness using ~. Strict Switches all pattern bindings to be strict by default (as if they had a bang using BangPatterns), ordinary patterns are recovered using ~. Implies StrictData. ApplicativeDo Allows do-notation for types that are Applicative as well as Monad. When enabled, desugaring do notation tries to use (*) and fmap and join as far as possible. DuplicateRecordFields Allow records to use duplicated field labels for accessors. TypeApplications Enable explicit type applications with the syntax id @Int. TypeInType Dissolve the distinction between types and kinds, allowing the compiler to reason about kind equality and therefore enabling GADTs to be promoted to the type-level. UndecidableSuperClasses Allow recursive (and therefore undecidable) super-class relationships. MonadFailDesugaring A temporary extension to help library authors check if their code will compile with the new planned desugaring of fail. TemplateHaskellQuotes A subset of TemplateHaskell including only quoting. OverloadedLabels Allows use of the #label syntax. TypeFamilyDependencies Allow functional dependency annotations on type families to declare them as injective. DerivingStrategies Allow multiple deriving clauses, each optionally qualified with a strategy. DerivingVia Enable deriving instances via types of the same runtime representation. Implies DerivingStrategies. UnboxedSums Enable the use of unboxed sum syntax. HexFloatLiterals Allow use of hexadecimal literal notation for floating-point values. BlockArguments Allow do blocks etc. in argument position. NumericUnderscores Allow use of underscores in numeric literals. QuantifiedConstraints Allow forall in constraints. StarIsType Have * refer to Type. EmptyDataDeriving Liberalises deriving to provide instances for empty data types. CUSKs Enable detection of complete user-supplied kind signatures. ImportQualifiedPost Allows the syntax import M qualified. StandaloneKindSignatures Allow the use of standalone kind signatures. UnliftedNewtypes Enable unlifted newtypes. LexicalNegation Use whitespace to determine whether the minus sign stands for negation or subtraction. QualifiedDo Enable qualified do-notation desugaring. LinearTypes Enable linear types. RequiredTypeArguments Allow the use of visible forall in types of terms. FieldSelectors Enable the generation of selector functions corresponding to record fields. OverloadedRecordDot Enable the use of record dot-accessor and updater syntax OverloadedRecordUpdate Provides record . syntax in record updates, e.g. x {foo.bar = 1}. UnliftedDatatypes Enable data types for which an unlifted or levity-polymorphic result kind is inferred. AlternativeLayoutRule Undocumented parsing-related extensions introduced in GHC 7.0. AlternativeLayoutRuleTransitional Undocumented parsing-related extensions introduced in GHC 7.0. RelaxedLayout Undocumented parsing-related extensions introduced in GHC 7.2.

#### Instances

Instances details