Language.Haskell.Syntax

HsEVar HsQName	variable
HsEAbs HsQName	`T`: a class or datatype exported abstractly, or a type synonym.
HsEThingAll HsQName	`T(..)`: a class exported with all of its methods, or a datatype exported with all of its constructors.
HsEThingWith HsQName [HsCName]	`T(C_1,...,C_n)`: a class exported with some of its methods, or a datatype exported with some of its constructors.
HsEModuleContents Module	`module M`: re-export a module.

Instances

Data HsExportSpec

Eq HsExportSpec

Pretty HsExportSpec

Show HsExportSpec

Typeable HsExportSpec

data HsImportDecl

Source

Import declaration.

Constructors

HsImportDecl

importLoc :: SrcLoc	position of the `import` keyword.
importModule :: Module	name of the module imported.
importQualified :: Bool	imported `qualified`?
importAs :: (Maybe Module)	optional alias name in an `as` clause.
importSpecs :: (Maybe (Bool, [HsImportSpec]))	optional list of import specifications. The `Bool` is `True` if the names are excluded by `hiding`.

Instances

Typeable HsImportDecl

data HsImportSpec

Source

Import specification.

Constructors

HsIVar HsName	variable
HsIAbs HsName	`T`: the name of a class, datatype or type synonym.
HsIThingAll HsName	`T(..)`: a class imported with all of its methods, or a datatype imported with all of its constructors.
HsIThingWith HsName [HsCName]	`T(C_1,...,C_n)`: a class imported with some of its methods, or a datatype imported with some of its constructors.

Instances

Typeable HsImportSpec

data HsAssoc

Source

Associativity of an operator.

Constructors

HsAssocNone	non-associative operator (declared with `infix`)
HsAssocLeft	left-associative operator (declared with `infixl`).
HsAssocRight	right-associative operator (declared with `infixr`)

Instances

data HsDecl

Constructors

HsTypeDecl SrcLoc HsName [HsName] HsType
HsDataDecl SrcLoc HsContext HsName [HsName] [HsConDecl] [HsQName]
HsInfixDecl SrcLoc HsAssoc Int [HsOp]
HsNewTypeDecl SrcLoc HsContext HsName [HsName] HsConDecl [HsQName]
HsClassDecl SrcLoc HsContext HsName [HsName] [HsDecl]
HsInstDecl SrcLoc HsContext HsQName [HsType] [HsDecl]
HsDefaultDecl SrcLoc [HsType]
HsTypeSig SrcLoc [HsName] HsQualType
HsFunBind [HsMatch]
HsPatBind SrcLoc HsPat HsRhs [HsDecl]
HsForeignImport SrcLoc String HsSafety String HsName HsType
HsForeignExport SrcLoc String String HsName HsType

Instances

data HsConDecl

Declaration of a data constructor.

Constructors

HsConDecl SrcLoc HsName [HsBangType]	ordinary data constructor
HsRecDecl SrcLoc HsName [([HsName], HsBangType)]	record constructor

Instances

data HsBangType

The type of a constructor argument or field, optionally including a strictness annotation.

Constructors

HsBangedTy HsType	strict component, marked with "`!`"
HsUnBangedTy HsType	non-strict component

Instances

data HsMatch

Clauses of a function binding.

Constructors

HsMatch SrcLoc HsName [HsPat] HsRhs [HsDecl]

Instances

data HsRhs

The right hand side of a function or pattern binding.

Constructors

HsUnGuardedRhs HsExp	unguarded right hand side (exp)
HsGuardedRhss [HsGuardedRhs]	guarded right hand side (gdrhs)

Instances

data HsGuardedRhs

Source

A guarded right hand side | exp = exp. The first expression will be Boolean-valued.

Safety level for invoking a foreign entity

Constructors

HsGuardedRhs SrcLoc HsExp HsExp

Instances

Typeable HsGuardedRhs

data HsSafety

Source

Constructors

HsSafe	call may generate callbacks
HsUnsafe	call will not generate callbacks

Instances

Class Assertions and Contexts

data HsQualType

Source

A type qualified with a context. An unqualified type has an empty context.

Constructors

HsQualType HsContext HsType

Instances

type HsContext = [HsAsst]

Source

type HsAsst = (HsQName, [HsType])

Source

Class assertions. In Haskell 98, the argument would be a tyvar, but this definition allows multiple parameters, and allows them to be types.

Types

data HsType

Source

Haskell types and type constructors.

Constructors

HsTyFun HsType HsType	function type
HsTyTuple [HsType]	tuple type
HsTyApp HsType HsType	application of a type constructor
HsTyVar HsName	type variable
HsTyCon HsQName	named type or type constructor

Instances

data HsExp

Haskell expressions.

Notes:

Because it is difficult for parsers to distinguish patterns from expressions, they typically parse them in the same way and then check that they have the appropriate form. Hence the expression type includes some forms that are found only in patterns. After these checks, these constructors should not be used.
The parser does not take precedence and associativity into account, so it will leave HsInfixApps associated to the left.
The Pretty instance for HsExp does not add parentheses in printing.

Constructors

HsVar HsQName	variable
HsCon HsQName	data constructor
HsLit HsLiteral	literal constant
HsInfixApp HsExp HsQOp HsExp	infix application
HsApp HsExp HsExp	ordinary application
HsNegApp HsExp	negation expression `-` exp
HsLambda SrcLoc [HsPat] HsExp	lambda expression
HsLet [HsDecl] HsExp	local declarations with `let`
HsIf HsExp HsExp HsExp	`if` exp `then` exp `else` exp
HsCase HsExp [HsAlt]	`case` exp `of` alts
HsDo [HsStmt]	`do`-expression: the last statement in the list should be an expression.
HsTuple [HsExp]	tuple expression
HsList [HsExp]	list expression
HsParen HsExp	parenthesized expression
HsLeftSection HsExp HsQOp	left section `(`exp qop`)`
HsRightSection HsQOp HsExp	right section `(`qop exp`)`
HsRecConstr HsQName [HsFieldUpdate]	record construction expression
HsRecUpdate HsExp [HsFieldUpdate]	record update expression
HsEnumFrom HsExp	unbounded arithmetic sequence, incrementing by 1
HsEnumFromTo HsExp HsExp	bounded arithmetic sequence, incrementing by 1
HsEnumFromThen HsExp HsExp	unbounded arithmetic sequence, with first two elements given
HsEnumFromThenTo HsExp HsExp HsExp	bounded arithmetic sequence, with first two elements given
HsListComp HsExp [HsStmt]	list comprehension
HsExpTypeSig SrcLoc HsExp HsQualType	expression type signature
HsAsPat HsName HsExp	patterns only
HsWildCard	patterns only
HsIrrPat HsExp	patterns only

Instances

data HsStmt

This type represents both stmt in a do-expression, and qual in a list comprehension.

Constructors

HsGenerator SrcLoc HsPat HsExp	a generator pat `<-` exp
HsQualifier HsExp	an exp by itself: in a `do`-expression, an action whose result is discarded; in a list comprehension, a guard expression
HsLetStmt [HsDecl]	local bindings

Instances

data HsFieldUpdate

Source

An fbind in a labeled record construction or update expression.

Constructors

HsFieldUpdate HsQName HsExp

Instances

Typeable HsFieldUpdate

data HsAlt

Source

An alt in a case expression.

Constructors

HsAlt SrcLoc HsPat HsGuardedAlts [HsDecl]

Instances

data HsGuardedAlts

Source

Constructors

HsUnGuardedAlt HsExp	`->` exp
HsGuardedAlts [HsGuardedAlt]	gdpat

Instances

Typeable HsGuardedAlts

data HsGuardedAlt

Source

A guarded alternative | exp -> exp. The first expression will be Boolean-valued.

Constructors

HsGuardedAlt SrcLoc HsExp HsExp

Instances

Typeable HsGuardedAlt

Patterns

data HsPat

Source

A pattern, to be matched against a value.

Constructors

HsPVar HsName	variable
HsPLit HsLiteral	literal constant
HsPNeg HsPat	negated pattern
HsPInfixApp HsPat HsQName HsPat	pattern with infix data constructor
HsPApp HsQName [HsPat]	data constructor and argument patterns
HsPTuple [HsPat]	tuple pattern
HsPList [HsPat]	list pattern
HsPParen HsPat	parenthesized pattern
HsPRec HsQName [HsPatField]	labelled pattern
HsPAsPat HsName HsPat	`@`-pattern
HsPWildCard	wildcard pattern (`_`)
HsPIrrPat HsPat	irrefutable pattern (`~`)

Instances

data HsPatField

An fpat in a labeled record pattern.

Constructors

HsPFieldPat HsQName HsPat

Instances

data HsLiteral

literal. Values of this type hold the abstract value of the literal, not the precise string representation used. For example, 10, 0o12 and 0xa have the same representation.

Constructors

HsChar Char	character literal
HsString String	string literal
HsInt Integer	integer literal
HsFrac Rational	floating point literal
HsCharPrim Char	GHC unboxed character literal
HsStringPrim String	GHC unboxed string literal
HsIntPrim Integer	GHC unboxed integer literal
HsFloatPrim Rational	GHC unboxed float literal
HsDoublePrim Rational	GHC unboxed double literal

Instances

Variables, Constructors and Operators

newtype Module

Source

The name of a Haskell module.

Constructors

Module String

Instances

data HsQName

This type is used to represent qualified variables, and also qualified constructors.

Constructors

Qual Module HsName	name qualified with a module name
UnQual HsName	unqualified name
Special HsSpecialCon	built-in constructor with special syntax

Instances

data HsName

This type is used to represent variables, and also constructors.

Constructors

HsIdent String	varid or conid
HsSymbol String	varsym or consym

Instances

data HsQOp

Possibly qualified infix operators (qop), appearing in expressions.

Constructors

HsQVarOp HsQName	variable operator (qvarop)
HsQConOp HsQName	constructor operator (qconop)

Instances

data HsOp

Operators, appearing in infix declarations.

Constructors

HsVarOp HsName	variable operator (varop)
HsConOp HsName	constructor operator (conop)

Instances

data HsSpecialCon

Source

Constructors with special syntax. These names are never qualified, and always refer to builtin type or data constructors.

Constructors

HsUnitCon	unit type and data constructor `()`
HsListCon	list type constructor `[]`
HsFunCon	function type constructor `->`
HsTupleCon Int	n-ary tuple type and data constructors `(,)` etc
HsCons	list data constructor `(:)`