Portability | portable |
---|---|
Stability | experimental |
Maintainer | libraries@haskell.org |
Safe Haskell | None |
Language.Haskell.Syntax
Contents
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.
- data HsModule = HsModule SrcLoc Module (Maybe [HsExportSpec]) [HsImportDecl] [HsDecl]
- data HsExportSpec
- 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
- 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]
- | HsForeignImport SrcLoc String HsSafety String HsName HsType
- | HsForeignExport SrcLoc String String HsName HsType
- data HsConDecl
- = HsConDecl SrcLoc HsName [HsBangType]
- | HsRecDecl SrcLoc HsName [([HsName], HsBangType)]
- data HsBangType
- data HsMatch = HsMatch SrcLoc HsName [HsPat] HsRhs [HsDecl]
- data HsRhs
- data HsGuardedRhs = HsGuardedRhs SrcLoc HsExp HsExp
- data HsSafety
- data HsQualType = HsQualType HsContext HsType
- type HsContext = [HsAsst]
- type HsAsst = (HsQName, [HsType])
- data HsType
- 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
- data HsGuardedAlt = HsGuardedAlt SrcLoc HsExp HsExp
- data 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
- data HsName
- data HsQOp
- data HsOp
- data HsSpecialCon
- = HsUnitCon
- | HsListCon
- | HsFunCon
- | HsTupleCon Int
- | HsCons
- data HsCName
- 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
- 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] |
data HsExportSpec
Export specification.
Constructors
HsEVar HsQName | variable |
HsEAbs HsQName |
|
HsEThingAll HsQName |
|
HsEThingWith HsQName [HsCName] |
|
HsEModuleContents Module |
|
Instances
Eq HsExportSpec | |
Data HsExportSpec | |
Show HsExportSpec | |
Typeable HsExportSpec | |
Pretty HsExportSpec |
data HsImportDecl
Import declaration.
Constructors
HsImportDecl | |
Fields
|
Instances
Eq HsImportDecl | |
Data HsImportDecl | |
Show HsImportDecl | |
Typeable HsImportDecl | |
Pretty HsImportDecl |
data HsImportSpec
Import specification.
Constructors
HsIVar HsName | variable |
HsIAbs HsName |
|
HsIThingAll HsName |
|
HsIThingWith HsName [HsCName] |
|
Instances
Eq HsImportSpec | |
Data HsImportSpec | |
Show HsImportSpec | |
Typeable HsImportSpec | |
Pretty HsImportSpec |
data HsAssoc
Associativity of an operator.
Constructors
HsAssocNone | non-associative operator (declared with |
HsAssocLeft | left-associative operator (declared with |
HsAssocRight | right-associative operator (declared with |
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] | |
HsForeignImport SrcLoc String HsSafety String HsName HsType | |
HsForeignExport SrcLoc String String HsName HsType |
data HsConDecl
Declaration of a data constructor.
Constructors
HsConDecl SrcLoc HsName [HsBangType] | ordinary data constructor |
HsRecDecl SrcLoc HsName [([HsName], HsBangType)] | record constructor |
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
Eq HsBangType | |
Data HsBangType | |
Show HsBangType | |
Typeable HsBangType | |
Pretty HsBangType |
data HsMatch
Clauses of a function binding.
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) |
data HsGuardedRhs
A guarded right hand side |
exp =
exp.
The first expression will be Boolean-valued.
Constructors
HsGuardedRhs SrcLoc HsExp HsExp |
Instances
Eq HsGuardedRhs | |
Data HsGuardedRhs | |
Show HsGuardedRhs | |
Typeable HsGuardedRhs | |
Pretty HsGuardedRhs |
data HsSafety
Safety level for invoking a foreign entity
Class Assertions and Contexts
data HsQualType
A type qualified with a context. An unqualified type has an empty context.
Constructors
HsQualType HsContext HsType |
Instances
Eq HsQualType | |
Data HsQualType | |
Show HsQualType | |
Typeable HsQualType | |
Pretty HsQualType |
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.
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 forHsExp
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 |
HsLambda SrcLoc [HsPat] HsExp | lambda expression |
HsLet [HsDecl] HsExp | local declarations with |
HsIf HsExp HsExp HsExp |
|
HsCase HsExp [HsAlt] |
|
HsDo [HsStmt] |
|
HsTuple [HsExp] | tuple expression |
HsList [HsExp] | list expression |
HsParen HsExp | parenthesized expression |
HsLeftSection HsExp HsQOp | left section |
HsRightSection HsQOp HsExp | right section |
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 |
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 |
HsQualifier HsExp | an exp by itself: in a |
HsLetStmt [HsDecl] | local bindings |
data HsFieldUpdate
An fbind in a labeled record construction or update expression.
Constructors
HsFieldUpdate HsQName HsExp |
Instances
Eq HsFieldUpdate | |
Data HsFieldUpdate | |
Show HsFieldUpdate | |
Typeable HsFieldUpdate | |
Pretty HsFieldUpdate |
data HsGuardedAlts
Constructors
HsUnGuardedAlt HsExp |
|
HsGuardedAlts [HsGuardedAlt] | gdpat |
Instances
Eq HsGuardedAlts | |
Data HsGuardedAlts | |
Show HsGuardedAlts | |
Typeable HsGuardedAlts | |
Pretty HsGuardedAlts |
data HsGuardedAlt
A guarded alternative |
exp ->
exp.
The first expression will be Boolean-valued.
Constructors
HsGuardedAlt SrcLoc HsExp HsExp |
Instances
Eq HsGuardedAlt | |
Data HsGuardedAlt | |
Show HsGuardedAlt | |
Typeable HsGuardedAlt | |
Pretty 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 |
|
HsPWildCard | wildcard pattern ( |
HsPIrrPat HsPat | irrefutable pattern ( |
data HsPatField
An fpat in a labeled record pattern.
Constructors
HsPFieldPat HsQName HsPat |
Instances
Eq HsPatField | |
Data HsPatField | |
Show HsPatField | |
Typeable HsPatField | |
Pretty 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 |
Variables, Constructors and Operators
data HsQName
This type is used to represent qualified variables, and also qualified constructors.
data HsName
This type is used to represent variables, and also constructors.
data HsQOp
Possibly qualified infix operators (qop), appearing in expressions.
data HsOp
Operators, appearing in infix
declarations.
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 |
HsCons | list data constructor |
Instances
Eq HsSpecialCon | |
Data 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.
Builtin names
Modules
Main function of a program
Constructors
tuple_con_name :: Int -> HsQName
Type constructors
tuple_tycon_name :: Int -> HsQName
unit_tycon :: HsType
list_tycon :: HsType
tuple_tycon :: Int -> HsType