{-# LANGUAGE CPP #-} {-# LANGUAGE DeriveDataTypeable #-} ----------------------------------------------------------------------------- -- | -- Module : Language.Haskell.Syntax -- Copyright : (c) The GHC Team, 1997-2000 -- License : BSD-3-Clause -- -- Maintainer : Andreas Abel -- Stability : stable -- Portability : portable -- -- A suite of datatypes describing the abstract syntax of -- plus a few extensions: -- -- * multi-parameter type classes -- -- * parameters of type class assertions are unrestricted -- -- For GHC, we also derive 'Typeable' and 'Data' for all types. ----------------------------------------------------------------------------- module Language.Haskell.Syntax ( -- * Modules HsModule(..), HsExportSpec(..), HsImportDecl(..), HsImportSpec(..), HsAssoc(..), -- * Declarations HsDecl(..), HsConDecl(..), HsBangType(..), HsMatch(..), HsRhs(..), HsGuardedRhs(..), HsSafety(..), -- * Class Assertions and Contexts HsQualType(..), HsContext, HsAsst, -- * Types HsType(..), -- * Expressions HsExp(..), HsStmt(..), HsFieldUpdate(..), HsAlt(..), HsGuardedAlts(..), HsGuardedAlt(..), -- * Patterns HsPat(..), HsPatField(..), -- * Literals HsLiteral(..), -- * Variables, Constructors and Operators Module(..), HsQName(..), HsName(..), HsQOp(..), HsOp(..), HsSpecialCon(..), HsCName(..), -- * Builtin names -- ** Modules prelude_mod, main_mod, -- ** Main function of a program main_name, -- ** Constructors unit_con_name, tuple_con_name, list_cons_name, unit_con, tuple_con, -- ** Type constructors unit_tycon_name, fun_tycon_name, list_tycon_name, tuple_tycon_name, unit_tycon, fun_tycon, list_tycon, tuple_tycon, -- * Source coordinates SrcLoc(..), ) where #ifdef __GLASGOW_HASKELL__ import Data.Generics.Basics import Data.Generics.Instances () #endif -- | A position in the source. data SrcLoc = SrcLoc { srcFilename :: String, srcLine :: Int, srcColumn :: Int } #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | The name of a Haskell module. newtype Module = Module String #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | Constructors with special syntax. -- These names are never qualified, and always refer to builtin type or -- data constructors. data HsSpecialCon = 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 @(:)@. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | This type is used to represent qualified variables, and also -- qualified constructors. data HsQName = Qual Module HsName -- ^ Name qualified with a module name. | UnQual HsName -- ^ Unqualified name. | Special HsSpecialCon -- ^ Built-in constructor with special syntax. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | This type is used to represent variables, and also constructors. data HsName = HsIdent String -- ^ /varid/ or /conid/. | HsSymbol String -- ^ /varsym/ or /consym/. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | Possibly qualified infix operators (/qop/), appearing in expressions. data HsQOp = HsQVarOp HsQName -- ^ Variable operator (/qvarop/). | HsQConOp HsQName -- ^ Constructor operator (/qconop/). #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | Operators, appearing in @infix@ declarations. data HsOp = HsVarOp HsName -- ^ Variable operator (/varop/). | HsConOp HsName -- ^ Constructor operator (/conop/). #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | A name (/cname/) of a component of a class or data type in an @import@ -- or export specification. data HsCName = HsVarName HsName -- ^ Name of a method or field. | HsConName HsName -- ^ Name of a data constructor. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | A Haskell source module. data HsModule = HsModule SrcLoc Module (Maybe [HsExportSpec]) [HsImportDecl] [HsDecl] #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Export specification. data HsExportSpec = 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. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Import declaration. data HsImportDecl = 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@. } #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Import specification. data HsImportSpec = 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. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Associativity of an operator. data HsAssoc = HsAssocNone -- ^ Non-associative operator (declared with @infix@). | HsAssocLeft -- ^ Left-associative operator (declared with @infixl@). | HsAssocRight -- ^ Right-associative operator (declared with @infixr@). #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif 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 {-where-} [HsDecl] | HsForeignImport SrcLoc String HsSafety String HsName HsType | HsForeignExport SrcLoc String String HsName HsType #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Clauses of a function binding. data HsMatch = HsMatch SrcLoc HsName [HsPat] HsRhs {-where-} [HsDecl] #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Declaration of a data constructor. data HsConDecl = HsConDecl SrcLoc HsName [HsBangType] -- ^ Ordinary data constructor. | HsRecDecl SrcLoc HsName [([HsName],HsBangType)] -- ^ Record constructor. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | The type of a constructor argument or field, optionally including -- a strictness annotation. data HsBangType = HsBangedTy HsType -- ^ Strict component, marked with \"@!@\". | HsUnBangedTy HsType -- ^ Non-strict component. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | The right hand side of a function or pattern binding. data HsRhs = HsUnGuardedRhs HsExp -- ^ Unguarded right hand side (/exp/). | HsGuardedRhss [HsGuardedRhs] -- ^ Guarded right hand side (/gdrhs/). #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | A guarded right hand side @|@ /exp/ @=@ /exp/. -- The first expression will be Boolean-valued. data HsGuardedRhs = HsGuardedRhs SrcLoc HsExp HsExp #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Safety level for invoking a foreign entity. data HsSafety = HsSafe -- ^ Call may generate callbacks. | HsUnsafe -- ^ Call will not generate callbacks. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Ord,Show,Typeable,Data) #else deriving (Eq,Ord,Show) #endif -- | A type qualified with a context. -- An unqualified type has an empty context. data HsQualType = HsQualType HsContext HsType #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | Haskell types and type constructors. data HsType = 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. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif type HsContext = [HsAsst] -- | Class assertions. -- In Haskell 98, the argument would be a /tyvar/, but this definition -- allows multiple parameters, and allows them to be /type/s. type HsAsst = (HsQName,[HsType]) -- | /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. data HsLiteral = 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. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | 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 'Language.Haskell.Pretty.Pretty' instance for 'HsExp' does not -- add parentheses in printing. data HsExp = 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) #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | A pattern, to be matched against a value. data HsPat = 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 (@~@). #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | An /fpat/ in a labeled record pattern. data HsPatField = HsPFieldPat HsQName HsPat #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | This type represents both /stmt/ in a @do@-expression, -- and /qual/ in a list comprehension. data HsStmt = 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. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | An /fbind/ in a labeled record construction or update expression. data HsFieldUpdate = HsFieldUpdate HsQName HsExp #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | An /alt/ in a @case@ expression. data HsAlt = HsAlt SrcLoc HsPat HsGuardedAlts [HsDecl] #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif data HsGuardedAlts = HsUnGuardedAlt HsExp -- ^ @->@ /exp/. | HsGuardedAlts [HsGuardedAlt] -- ^ /gdpat/. #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif -- | A guarded alternative @|@ /exp/ @->@ /exp/. -- The first expression will be Boolean-valued. data HsGuardedAlt = HsGuardedAlt SrcLoc HsExp HsExp #ifdef __GLASGOW_HASKELL__ deriving (Eq,Show,Typeable,Data) #else deriving (Eq,Show) #endif ----------------------------------------------------------------------------- -- Builtin names. prelude_mod, main_mod :: Module prelude_mod = Module "Prelude" main_mod = Module "Main" main_name :: HsName main_name = HsIdent "main" unit_con_name :: HsQName unit_con_name = Special HsUnitCon tuple_con_name :: Int -> HsQName tuple_con_name i = Special (HsTupleCon (i+1)) list_cons_name :: HsQName list_cons_name = Special HsCons unit_con :: HsExp unit_con = HsCon unit_con_name tuple_con :: Int -> HsExp tuple_con i = HsCon (tuple_con_name i) unit_tycon_name, fun_tycon_name, list_tycon_name :: HsQName unit_tycon_name = unit_con_name fun_tycon_name = Special HsFunCon list_tycon_name = Special HsListCon tuple_tycon_name :: Int -> HsQName tuple_tycon_name i = tuple_con_name i unit_tycon, fun_tycon, list_tycon :: HsType unit_tycon = HsTyCon unit_tycon_name fun_tycon = HsTyCon fun_tycon_name list_tycon = HsTyCon list_tycon_name tuple_tycon :: Int -> HsType tuple_tycon i = HsTyCon (tuple_tycon_name i)