Language.Haskell.Syntax

| Haskell Hierarchical Libraries (haskell-src package) | Contents | Index
Language.Haskell.Syntax |
Portability | portable
Stability | experimental
Maintainer | libraries@haskell.org
Contents
Modules Declarations Class Assertions and Contexts Types Expressions Patterns Literals Variables, Constructors and Operators Builtin names Modules Main function of a program Constructors Special identifiers Type constructors Source coordinates
Description
A suite of datatypes describing the abstract syntax of Haskell 98 http://www.haskell.org/onlinereport/ plus a few extensions: multi-parameter type classes parameters of type class assertions are unrestricted This module has been changed so that show is a real show. For GHC, we also derive Typeable and Data for all types.
Synopsis
data HsModule = HsModule SrcLoc Module (Maybe [HsExportSpec]) [HsImportDecl] [HsDecl]
data HsExportSpec
= HsEVar HsQName
| HsEAbs HsQName
| HsEThingAll HsQName
| HsEThingWith HsQName [HsCName]
| HsEModuleContents Module
data HsImportDecl = HsImportDecl {
importLoc :: SrcLoc
importModule :: Module
importQualified :: Bool
importAs :: (Maybe Module)
importSpecs :: (Maybe (Bool, [HsImportSpec]))
}
data HsImportSpec
= HsIVar HsName
| HsIAbs HsName
| HsIThingAll HsName
| HsIThingWith HsName [HsCName]
data HsAssoc
= HsAssocNone
| HsAssocLeft
| HsAssocRight
data HsDecl
= 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]
data HsConDecl
= HsConDecl SrcLoc HsName [HsBangType]
| HsRecDecl SrcLoc HsName [([HsName], HsBangType)]
data HsBangType
= HsBangedTy HsType
| HsUnBangedTy HsType
data HsMatch = HsMatch SrcLoc HsName [HsPat] HsRhs [HsDecl]
data HsRhs
= HsUnGuardedRhs HsExp
| HsGuardedRhss [HsGuardedRhs]
data HsGuardedRhs = HsGuardedRhs SrcLoc HsExp HsExp
data HsQualType = HsQualType HsContext HsType
type HsContext = [HsAsst]
type HsAsst = (HsQName, [HsType])
data HsType
= HsTyFun HsType HsType
| HsTyTuple [HsType]
| HsTyApp HsType HsType
| HsTyVar HsName
| HsTyCon HsQName
data HsExp
= HsVar HsQName
| HsCon HsQName
| HsLit HsLiteral
| HsInfixApp HsExp HsQOp HsExp
| HsApp HsExp HsExp
| HsNegApp HsExp
| HsLambda SrcLoc [HsPat] HsExp
| HsLet [HsDecl] HsExp
| HsIf HsExp HsExp HsExp
| HsCase HsExp [HsAlt]
| HsDo [HsStmt]
| HsTuple [HsExp]
| HsList [HsExp]
| HsParen HsExp
| HsLeftSection HsExp HsQOp
| HsRightSection HsQOp HsExp
| HsRecConstr HsQName [HsFieldUpdate]
| HsRecUpdate HsExp [HsFieldUpdate]
| HsEnumFrom HsExp
| HsEnumFromTo HsExp HsExp
| HsEnumFromThen HsExp HsExp
| HsEnumFromThenTo HsExp HsExp HsExp
| HsListComp HsExp [HsStmt]
| HsExpTypeSig SrcLoc HsExp HsQualType
| HsAsPat HsName HsExp
| HsWildCard
| HsIrrPat HsExp
data HsStmt
= HsGenerator SrcLoc HsPat HsExp
| HsQualifier HsExp
| HsLetStmt [HsDecl]
data HsFieldUpdate = HsFieldUpdate HsQName HsExp
data HsAlt = HsAlt SrcLoc HsPat HsGuardedAlts [HsDecl]
data HsGuardedAlts
= HsUnGuardedAlt HsExp
| HsGuardedAlts [HsGuardedAlt]
data HsGuardedAlt = HsGuardedAlt SrcLoc HsExp HsExp
data HsPat
= HsPVar HsName
| HsPLit HsLiteral
| HsPNeg HsPat
| HsPInfixApp HsPat HsQName HsPat
| HsPApp HsQName [HsPat]
| HsPTuple [HsPat]
| HsPList [HsPat]
| HsPParen HsPat
| HsPRec HsQName [HsPatField]
| HsPAsPat HsName HsPat
| HsPWildCard
| HsPIrrPat HsPat
data HsPatField = HsPFieldPat HsQName HsPat
data HsLiteral
= HsChar Char
| HsString String
| HsInt Integer
| HsFrac Rational
| HsCharPrim Char
| HsStringPrim String
| HsIntPrim Integer
| HsFloatPrim Rational
| HsDoublePrim Rational
newtype Module = Module String
data HsQName
= Qual Module HsName
| UnQual HsName
| Special HsSpecialCon
data HsName
= HsIdent String
| HsSymbol String
data HsQOp
= HsQVarOp HsQName
| HsQConOp HsQName
data HsOp
= HsVarOp HsName
| HsConOp HsName
data HsSpecialCon
= HsUnitCon
| HsListCon
| HsFunCon
| HsTupleCon Int
| HsCons
data HsCName
= HsVarName HsName
| HsConName HsName
prelude_mod :: Module
main_mod :: Module
main_name :: HsName
unit_con_name :: HsQName
tuple_con_name :: Int -> HsQName
list_cons_name :: HsQName
unit_con :: HsExp
tuple_con :: Int -> HsExp
as_name :: HsName
qualified_name :: HsName
hiding_name :: HsName
minus_name :: HsName
pling_name :: HsName
unit_tycon_name :: HsQName
fun_tycon_name :: HsQName
list_tycon_name :: HsQName
tuple_tycon_name :: Int -> HsQName
unit_tycon :: HsType
fun_tycon :: HsType
list_tycon :: HsType
tuple_tycon :: Int -> HsType
data SrcLoc = SrcLoc {
srcFilename :: String
srcLine :: Int
srcColumn :: Int
}
Modules
data HsModule
A Haskell source module.
Constructors
HsModule SrcLoc Module (Maybe [HsExportSpec]) [HsImportDecl] [HsDecl] |
Instances
Data HsModule
Pretty HsModule
Show HsModule
Typeable HsModule
data HsExportSpec
Export specification.
Constructors
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
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
Data HsImportDecl
Eq HsImportDecl
Pretty HsImportDecl
Show HsImportDecl
Typeable HsImportDecl
data HsImportSpec
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
Data HsImportSpec
Eq HsImportSpec
Pretty HsImportSpec
Show HsImportSpec
Typeable HsImportSpec
data HsAssoc
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 HsAssoc
Eq HsAssoc
Pretty HsAssoc
Show HsAssoc
Typeable HsAssoc
Declarations
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] |
Instances
Data HsDecl
Eq HsDecl
Pretty HsDecl
Show HsDecl
Typeable HsDecl
data HsConDecl
Declaration of a data constructor.
Constructors
HsConDecl SrcLoc HsName [HsBangType] | ordinary data constructor
HsRecDecl SrcLoc HsName [([HsName], HsBangType)] | record constructor
Instances
Data HsConDecl
Eq HsConDecl
Pretty HsConDecl
Show HsConDecl
Typeable HsConDecl
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 HsBangType
Eq HsBangType
Pretty HsBangType
Show HsBangType
Typeable HsBangType
data HsMatch
Clauses of a function binding.
Constructors
HsMatch SrcLoc HsName [HsPat] HsRhs [HsDecl] |
Instances
Data HsMatch
Eq HsMatch
Pretty HsMatch
Show HsMatch
Typeable HsMatch
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 HsRhs
Eq HsRhs
Pretty HsRhs
Show HsRhs
Typeable HsRhs
data HsGuardedRhs
A guarded right hand side `|` exp `=` exp. The first expression will be Boolean-valued.
Constructors
HsGuardedRhs SrcLoc HsExp HsExp |
Instances
Data HsGuardedRhs
Eq HsGuardedRhs
Pretty HsGuardedRhs
Show HsGuardedRhs
Typeable HsGuardedRhs
Class Assertions and Contexts
data HsQualType
A type qualified with a context. An unqualified type has an empty context.
Constructors
HsQualType HsContext HsType |
Instances
Data HsQualType
Eq HsQualType
Pretty HsQualType
Show HsQualType
Typeable HsQualType
type HsContext = [HsAsst]
type HsAsst = (HsQName, [HsType])
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
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 HsType
Eq HsType
Pretty HsType
Show HsType
Typeable HsType
Expressions
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 `HsInfixApp`s 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 HsExp
Eq HsExp
Pretty HsExp
Show HsExp
Typeable HsExp
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 HsStmt
Eq HsStmt
Pretty HsStmt
Show HsStmt
Typeable HsStmt
data HsFieldUpdate
An fbind in a labeled record construction or update expression.
Constructors
HsFieldUpdate HsQName HsExp |
Instances
Data HsFieldUpdate
Eq HsFieldUpdate
Pretty HsFieldUpdate
Show HsFieldUpdate
Typeable HsFieldUpdate
data HsAlt
An alt in a `case` expression.
Constructors
HsAlt SrcLoc HsPat HsGuardedAlts [HsDecl] |
Instances
Data HsAlt
Eq HsAlt
Pretty HsAlt
Show HsAlt
Typeable HsAlt
data HsGuardedAlts
Constructors
HsUnGuardedAlt HsExp | `->` exp
HsGuardedAlts [HsGuardedAlt] | gdpat
Instances
Data HsGuardedAlts
Eq HsGuardedAlts
Pretty HsGuardedAlts
Show HsGuardedAlts
Typeable HsGuardedAlts
data HsGuardedAlt
A guarded alternative `|` exp `->` exp. The first expression will be Boolean-valued.
Constructors
HsGuardedAlt SrcLoc HsExp HsExp |
Instances
Data HsGuardedAlt
Eq HsGuardedAlt
Pretty HsGuardedAlt
Show HsGuardedAlt
Typeable HsGuardedAlt
Patterns
data HsPat
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 HsPat
Eq HsPat
Pretty HsPat
Show HsPat
Typeable HsPat
data HsPatField
An fpat in a labeled record pattern.
Constructors
HsPFieldPat HsQName HsPat |
Instances
Data HsPatField
Eq HsPatField
Pretty HsPatField
Show HsPatField
Typeable HsPatField
Literals
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
Data HsLiteral
Eq HsLiteral
Pretty HsLiteral
Show HsLiteral
Typeable HsLiteral
Variables, Constructors and Operators
newtype Module
The name of a Haskell module.
Constructors
Module String |
Instances
Data Module
Eq Module
Ord Module
Pretty Module
Show Module
Typeable Module
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 HsQName
Eq HsQName
Ord HsQName
Pretty HsQName
Show HsQName
Typeable HsQName
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 HsName
Eq HsName
Ord HsName
Pretty HsName
Show HsName
Typeable HsName
data HsQOp
Possibly qualified infix operators (qop), appearing in expressions.
Constructors
HsQVarOp HsQName | variable operator (qvarop)
HsQConOp HsQName | constructor operator (qconop)
Instances
Data HsQOp
Eq HsQOp
Ord HsQOp
Pretty HsQOp
Show HsQOp
Typeable HsQOp
data HsOp
Operators, appearing in `infix` declarations.
Constructors
HsVarOp HsName | variable operator (varop)
HsConOp HsName | constructor operator (conop)
Instances
Data HsOp
Eq HsOp
Ord HsOp
Pretty HsOp
Show HsOp
Typeable HsOp
data HsSpecialCon
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 `(:)`
Instances
Data HsSpecialCon
Eq HsSpecialCon
Ord HsSpecialCon
Show HsSpecialCon
Typeable HsSpecialCon
data HsCName
A name (cname) of a component of a class or data type in an `import` or export specification.
Constructors
HsVarName HsName | name of a method or field
HsConName HsName | name of a data constructor
Instances
Data HsCName
Eq HsCName
Ord HsCName
Pretty HsCName
Show HsCName
Typeable HsCName
Builtin names
Modules
prelude_mod :: Module
main_mod :: Module
Main function of a program
main_name :: HsName
Constructors
unit_con_name :: HsQName
tuple_con_name :: Int -> HsQName
list_cons_name :: HsQName
unit_con :: HsExp
tuple_con :: Int -> HsExp
Special identifiers
as_name :: HsName
qualified_name :: HsName
hiding_name :: HsName
minus_name :: HsName
pling_name :: HsName
Type constructors
unit_tycon_name :: HsQName
fun_tycon_name :: HsQName
list_tycon_name :: HsQName
tuple_tycon_name :: Int -> HsQName
unit_tycon :: HsType
fun_tycon :: HsType
list_tycon :: HsType
tuple_tycon :: Int -> HsType
Source coordinates
data SrcLoc
A position in the source.
Constructors
SrcLoc |
srcFilename :: String |
srcLine :: Int |
srcColumn :: Int |
Instances
Data SrcLoc
Eq SrcLoc
Ord SrcLoc
Show SrcLoc
Typeable SrcLoc
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