X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FhsSyn%2FHsPat.lhs;h=953d228942a0c85da06b8035a72c430609819740;hb=5d3051c66796dcf884b052f9e4afc3ed19b9f514;hp=71aba6b71fee48f3bce8c3a563e36ec0d9c9f001;hpb=9af77fa423926fbda946b31e174173d0ec5ebac8;p=ghc-hetmet.git diff --git a/ghc/compiler/hsSyn/HsPat.lhs b/ghc/compiler/hsSyn/HsPat.lhs index 71aba6b..953d228 100644 --- a/ghc/compiler/hsSyn/HsPat.lhs +++ b/ghc/compiler/hsSyn/HsPat.lhs @@ -5,113 +5,116 @@ \begin{code} module HsPat ( - Pat(..), InPat, OutPat, + Pat(..), InPat, OutPat, LPat, HsConDetails(..), hsConArgs, - mkPrefixConPat, mkCharLitPat, mkNilPat, + mkPrefixConPat, mkCharLitPat, mkNilPat, - failureFreePat, isWildPat, - patsAreAllCons, isConPat, isSigPat, - patsAreAllLits, isLitPat, - collectPatBinders, collectPatsBinders, - collectSigTysFromPat, collectSigTysFromPats + isBangHsBind, + patsAreAllCons, isConPat, isSigPat, isWildPat, + patsAreAllLits, isLitPat, isIrrefutableHsPat ) where #include "HsVersions.h" -import {-# SOURCE #-} HsExpr ( HsExpr ) +import {-# SOURCE #-} HsExpr ( SyntaxExpr ) -- friends: +import HsBinds ( DictBinds, HsBind(..), emptyLHsBinds, pprLHsBinds ) import HsLit ( HsLit(HsCharPrim), HsOverLit ) -import HsTypes ( HsType, SyntaxName, PostTcType ) +import HsTypes ( LHsType, PostTcType ) import BasicTypes ( Boxity, tupleParens ) -- others: +import PprCore ( {- instance OutputableBndr TyVar -} ) import TysWiredIn ( nilDataCon, charDataCon, charTy ) import Var ( TyVar ) import DataCon ( DataCon, dataConTyCon ) -import Maybes ( maybeToBool ) +import TyCon ( isProductTyCon ) import Outputable -import TyCon ( maybeTyConSingleCon ) import Type ( Type ) +import SrcLoc ( Located(..), unLoc, noLoc ) \end{code} \begin{code} -type InPat id = Pat id -- No 'Out' constructors -type OutPat id = Pat id -- No 'In' constructors +type InPat id = LPat id -- No 'Out' constructors +type OutPat id = LPat id -- No 'In' constructors + +type LPat id = Located (Pat id) data Pat id = ------------ Simple patterns --------------- WildPat PostTcType -- Wild card | VarPat id -- Variable - | LazyPat (Pat id) -- Lazy pattern - | AsPat id (Pat id) -- As pattern - | ParPat (Pat id) -- Parenthesised pattern + | VarPatOut id (DictBinds id) -- Used only for overloaded Ids; the + -- bindings give its overloaded instances + | LazyPat (LPat id) -- Lazy pattern + | AsPat (Located id) (LPat id) -- As pattern + | ParPat (LPat id) -- Parenthesised pattern + | BangPat (LPat id) -- Bang patterng ------------ Lists, tuples, arrays --------------- - | ListPat [Pat id] -- Syntactic list + | ListPat [LPat id] -- Syntactic list PostTcType -- The type of the elements - | TuplePat [Pat id] -- Tuple + | TuplePat [LPat id] -- Tuple Boxity -- UnitPat is TuplePat [] - - | PArrPat [Pat id] -- Syntactic parallel array + PostTcType + -- You might think that the PostTcType was redundant, but it's essential + -- data T a where + -- T1 :: Int -> T Int + -- f :: (T a, a) -> Int + -- f (T1 x, z) = z + -- When desugaring, we must generate + -- f = /\a. \v::a. case v of (t::T a, w::a) -> + -- case t of (T1 (x::Int)) -> + -- Note the (w::a), NOT (w::Int), because we have not yet + -- refined 'a' to Int. So we must know that the second component + -- of the tuple is of type 'a' not Int. See selectMatchVar + + | PArrPat [LPat id] -- Syntactic parallel array PostTcType -- The type of the elements ------------ Constructor patterns --------------- - | ConPatIn id - (HsConDetails id (Pat id)) + | ConPatIn (Located id) + (HsConDetails id (LPat id)) - | ConPatOut DataCon - (HsConDetails id (Pat id)) - Type -- The type of the pattern + | ConPatOut (Located DataCon) [TyVar] -- Existentially bound type variables [id] -- Ditto dictionaries + (DictBinds id) -- Bindings involving those dictionaries + (HsConDetails id (LPat id)) + Type -- The type of the pattern ------------ Literal and n+k patterns --------------- | LitPat HsLit -- Used for *non-overloaded* literal patterns: -- Int#, Char#, Int, Char, String, etc. - | NPatIn HsOverLit -- Always positive - (Maybe SyntaxName) -- Just (Name of 'negate') for negative - -- patterns, Nothing otherwise - - | NPatOut HsLit -- Used for literal patterns where there's an equality function to call - -- The literal is retained so that the desugarer can readily identify - -- equations with identical literal-patterns - -- Always HsInteger, HsRat or HsString. - -- Always HsInteger, HsRat or HsString. - -- *Unlike* NPatIn, for negative literals, the - -- literal is acutally negative! - Type -- Type of pattern, t - (HsExpr id) -- Of type t -> Bool; detects match - - | NPlusKPatIn id -- n+k pattern - HsOverLit -- It'll always be an HsIntegral - SyntaxName -- Name of '-' (see RnEnv.lookupSyntaxName) - - | NPlusKPatOut id - Integer - (HsExpr id) -- Of type t -> Bool; detects match - (HsExpr id) -- Of type t -> t; subtracts k + | NPat (HsOverLit id) -- ALWAYS positive + (Maybe (SyntaxExpr id)) -- Just (Name of 'negate') for negative + -- patterns, Nothing otherwise + (SyntaxExpr id) -- Equality checker, of type t->t->Bool + PostTcType -- Type of the pattern + | NPlusKPat (Located id) -- n+k pattern + (HsOverLit id) -- It'll always be an HsIntegral + (SyntaxExpr id) -- (>=) function, of type t->t->Bool + (SyntaxExpr id) -- Name of '-' (see RnEnv.lookupSyntaxName) ------------ Generics --------------- - | TypePat (HsType id) -- Type pattern for generic definitions + | TypePat (LHsType id) -- Type pattern for generic definitions -- e.g f{| a+b |} = ... -- These show up only in class declarations, -- and should be a top-level pattern ------------ Pattern type signatures --------------- - | SigPatIn (Pat id) -- Pattern with a type signature - (HsType id) + | SigPatIn (LPat id) -- Pattern with a type signature + (LHsType id) - | SigPatOut (Pat id) -- Pattern p - Type -- Type, t, of the whole pattern - (HsExpr id) -- Coercion function, - -- of type t -> typeof(p) + | SigPatOut (LPat id) -- Pattern with a type signature + Type ------------ Dictionary patterns (translation only) --------------- | DictPat -- Used when destructing Dictionaries with an explicit case @@ -124,7 +127,7 @@ HsConDetails is use both for patterns and for data type declarations \begin{code} data HsConDetails id arg = PrefixCon [arg] -- C p1 p2 p3 - | RecCon [(id, arg)] -- C { x = p1, y = p2 } + | RecCon [(Located id, arg)] -- C { x = p1, y = p2 } | InfixCon arg arg -- p1 `C` p2 hsConArgs :: HsConDetails id arg -> [arg] @@ -144,9 +147,8 @@ hsConArgs (InfixCon p1 p2) = [p1,p2] instance (OutputableBndr name) => Outputable (Pat name) where ppr = pprPat -pprPat :: (OutputableBndr name) => Pat name -> SDoc - -pprPat (VarPat var) -- Print with type info if -dppr-debug is on +pprPatBndr :: OutputableBndr name => name -> SDoc +pprPatBndr var -- Print with type info if -dppr-debug is on = getPprStyle $ \ sty -> if debugStyle sty then parens (pprBndr LambdaBind var) -- Could pass the site to pprPat @@ -154,44 +156,46 @@ pprPat (VarPat var) -- Print with type info if -dppr-debug is on else ppr var +pprPat :: (OutputableBndr name) => Pat name -> SDoc +pprPat (VarPat var) = pprPatBndr var +pprPat (VarPatOut var bs) = parens (pprPatBndr var <+> braces (ppr bs)) pprPat (WildPat _) = char '_' pprPat (LazyPat pat) = char '~' <> ppr pat +pprPat (BangPat pat) = char '!' <> ppr pat pprPat (AsPat name pat) = parens (hcat [ppr name, char '@', ppr pat]) -pprPat (ParPat pat) = parens (pprPat pat) - -pprPat (ListPat pats _) = brackets (interpp'SP pats) -pprPat (PArrPat pats _) = pabrackets (interpp'SP pats) -pprPat (TuplePat pats bx) = tupleParens bx (interpp'SP pats) - -pprPat (ConPatIn c details) = pprConPat c details -pprPat (ConPatOut c details _ _ _) = pprConPat c details +pprPat (ParPat pat) = parens (ppr pat) +pprPat (ListPat pats _) = brackets (interpp'SP pats) +pprPat (PArrPat pats _) = pabrackets (interpp'SP pats) +pprPat (TuplePat pats bx _) = tupleParens bx (interpp'SP pats) + +pprPat (ConPatIn con details) = pprUserCon con details +pprPat (ConPatOut con tvs dicts binds details _) + = getPprStyle $ \ sty -> -- Tiresome; in TcBinds.tcRhs we print out a + if debugStyle sty then -- typechecked Pat in an error message, + -- and we want to make sure it prints nicely + ppr con <+> sep [ hsep (map pprPatBndr tvs) <+> hsep (map pprPatBndr dicts), + pprLHsBinds binds, pprConArgs details] + else pprUserCon con details pprPat (LitPat s) = ppr s -pprPat (NPatIn l _) = ppr l -pprPat (NPatOut l _ _) = ppr l -pprPat (NPlusKPatIn n k _) = hcat [ppr n, char '+', ppr k] -pprPat (NPlusKPatOut n k _ _) = hcat [ppr n, char '+', integer k] - -pprPat (TypePat ty) = ptext SLIT("{|") <> ppr ty <> ptext SLIT("|}") - -pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty -pprPat (SigPatOut pat ty _) = ppr pat <+> dcolon <+> ppr ty - -pprPat (DictPat dicts methods) - = parens (sep [ptext SLIT("{-dict-}"), - brackets (interpp'SP dicts), - brackets (interpp'SP methods)]) - - - -pprConPat con (PrefixCon pats) = ppr con <+> interppSP pats -- inner ParPats supply the necessary parens. -pprConPat con (InfixCon pat1 pat2) = hsep [ppr pat1, ppr con, ppr pat2] -- ParPats put in parens - -- ToDo: use pprSym to print op (but this involves fiddling various - -- contexts & I'm lazy...); *PatIns are *rarely* printed anyway... (WDP) -pprConPat con (RecCon rpats) - = ppr con <+> braces (hsep (punctuate comma (map (pp_rpat) rpats))) - where - pp_rpat (v, p) = hsep [ppr v, char '=', ppr p] +pprPat (NPat l Nothing _ _) = ppr l +pprPat (NPat l (Just _) _ _) = char '-' <> ppr l +pprPat (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k] +pprPat (TypePat ty) = ptext SLIT("{|") <> ppr ty <> ptext SLIT("|}") +pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty +pprPat (SigPatOut pat ty) = ppr pat <+> dcolon <+> ppr ty +pprPat (DictPat ds ms) = parens (sep [ptext SLIT("{-dict-}"), + brackets (interpp'SP ds), + brackets (interpp'SP ms)]) + +pprUserCon c (InfixCon p1 p2) = ppr p1 <+> ppr c <+> ppr p2 +pprUserCon c details = ppr c <+> pprConArgs details + +pprConArgs (PrefixCon pats) = interppSP pats +pprConArgs (InfixCon p1 p2) = interppSP [p1,p2] +pprConArgs (RecCon rpats) = braces (hsep (punctuate comma (map (pp_rpat) rpats))) + where + pp_rpat (v, p) = hsep [ppr v, char '=', ppr p] -- add parallel array brackets around a document @@ -210,13 +214,13 @@ pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") \begin{code} mkPrefixConPat :: DataCon -> [OutPat id] -> Type -> OutPat id -- Make a vanilla Prefix constructor pattern -mkPrefixConPat dc pats ty = ConPatOut dc (PrefixCon pats) ty [] [] +mkPrefixConPat dc pats ty = noLoc $ ConPatOut (noLoc dc) [] [] emptyLHsBinds (PrefixCon pats) ty mkNilPat :: Type -> OutPat id mkNilPat ty = mkPrefixConPat nilDataCon [] ty -mkCharLitPat :: Int -> OutPat id -mkCharLitPat c = mkPrefixConPat charDataCon [LitPat (HsCharPrim c)] charTy +mkCharLitPat :: Char -> OutPat id +mkCharLitPat c = mkPrefixConPat charDataCon [noLoc $ LitPat (HsCharPrim c)] charTy \end{code} @@ -250,128 +254,71 @@ patterns are treated specially, of course. The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are. \begin{code} -failureFreePat :: OutPat id -> Bool - -failureFreePat (WildPat _) = True -failureFreePat (VarPat _) = True -failureFreePat (LazyPat _) = True -failureFreePat (ParPat _) = True -failureFreePat (AsPat _ pat) = failureFreePat pat - -failureFreePat (ListPat _ _) = False -failureFreePat (PArrPat _ _) = False -failureFreePat (TuplePat pats _) = all failureFreePat pats - -failureFreePat (ConPatOut con ps _ _ _) = only_con con && failure_free_con ps - -failureFreePat (SigPatOut p _ _) = failureFreePat p - -failureFreePat (DictPat _ _) = True - -failureFreePat other_pat = False -- Literals, NPat - -failure_free_con (PrefixCon pats) = all failureFreePat pats -failure_free_con (InfixCon p1 p2) = failureFreePat p1 && failureFreePat p2 -failure_free_con (RecCon fs) = all (failureFreePat . snd) fs - -only_con con = maybeToBool (maybeTyConSingleCon (dataConTyCon con)) -\end{code} - -\begin{code} isWildPat (WildPat _) = True isWildPat other = False patsAreAllCons :: [Pat id] -> Bool patsAreAllCons pat_list = all isConPat pat_list -isConPat (AsPat _ pat) = isConPat pat -isConPat (ConPatIn _ _) = True -isConPat (ConPatOut _ _ _ _ _) = True -isConPat (ListPat _ _) = True -isConPat (PArrPat _ _) = True -isConPat (TuplePat _ _) = True -isConPat (DictPat ds ms) = (length ds + length ms) > 1 -isConPat other = False +isConPat (AsPat _ pat) = isConPat (unLoc pat) +isConPat (ConPatIn _ _) = True +isConPat (ConPatOut _ _ _ _ _ _) = True +isConPat (ListPat _ _) = True +isConPat (PArrPat _ _) = True +isConPat (TuplePat _ _ _) = True +isConPat (DictPat ds ms) = (length ds + length ms) > 1 +isConPat other = False -isSigPat (SigPatIn _ _) = True -isSigPat (SigPatOut _ _ _) = True -isSigPat other = False +isSigPat (SigPatIn _ _) = True +isSigPat (SigPatOut _ _) = True +isSigPat other = False patsAreAllLits :: [Pat id] -> Bool patsAreAllLits pat_list = all isLitPat pat_list -isLitPat (AsPat _ pat) = isLitPat pat +isLitPat (AsPat _ pat) = isLitPat (unLoc pat) isLitPat (LitPat _) = True -isLitPat (NPatIn _ _) = True -isLitPat (NPatOut _ _ _) = True -isLitPat (NPlusKPatIn _ _ _) = True -isLitPat (NPlusKPatOut _ _ _ _) = True +isLitPat (NPat _ _ _ _) = True +isLitPat (NPlusKPat _ _ _ _) = True isLitPat other = False -\end{code} - -%************************************************************************ -%* * -%* Gathering stuff out of patterns -%* * -%************************************************************************ - -This function @collectPatBinders@ works with the ``collectBinders'' -functions for @HsBinds@, etc. The order in which the binders are -collected is important; see @HsBinds.lhs@. - -It collects the bounds *value* variables in renamed patterns; type variables -are *not* collected. -\begin{code} -collectPatBinders :: Pat a -> [a] -collectPatBinders pat = collect pat [] - -collectPatsBinders :: [Pat a] -> [a] -collectPatsBinders pats = foldr collect [] pats - -collect (WildPat _) bndrs = bndrs -collect (VarPat var) bndrs = var : bndrs -collect (LazyPat pat) bndrs = collect pat bndrs -collect (AsPat a pat) bndrs = a : collect pat bndrs -collect (ParPat pat) bndrs = collect pat bndrs - -collect (ListPat pats _) bndrs = foldr collect bndrs pats -collect (PArrPat pats _) bndrs = foldr collect bndrs pats -collect (TuplePat pats _) bndrs = foldr collect bndrs pats - -collect (ConPatIn c ps) bndrs = foldr collect bndrs (hsConArgs ps) -collect (ConPatOut c ps _ _ ds) bndrs = ds ++ foldr collect bndrs (hsConArgs ps) - -collect (LitPat _) bndrs = bndrs -collect (NPatIn _ _) bndrs = bndrs -collect (NPatOut _ _ _) bndrs = bndrs - -collect (NPlusKPatIn n _ _) bndrs = n : bndrs -collect (NPlusKPatOut n _ _ _) bndrs = n : bndrs - -collect (SigPatIn pat _) bndrs = collect pat bndrs -collect (SigPatOut pat _ _) bndrs = collect pat bndrs -collect (TypePat ty) bndrs = bndrs -collect (DictPat ids1 ids2) bndrs = ids1 ++ ids2 ++ bndrs -\end{code} - -\begin{code} -collectSigTysFromPats :: [InPat name] -> [HsType name] -collectSigTysFromPats pats = foldr collect_pat [] pats - -collectSigTysFromPat :: InPat name -> [HsType name] -collectSigTysFromPat pat = collect_pat pat [] - -collect_pat (SigPatIn pat ty) acc = collect_pat pat (ty:acc) -collect_pat (TypePat ty) acc = ty:acc - -collect_pat (LazyPat pat) acc = collect_pat pat acc -collect_pat (AsPat a pat) acc = collect_pat pat acc -collect_pat (ParPat pat) acc = collect_pat pat acc -collect_pat (ListPat pats _) acc = foldr collect_pat acc pats -collect_pat (PArrPat pats _) acc = foldr collect_pat acc pats -collect_pat (TuplePat pats _) acc = foldr collect_pat acc pats -collect_pat (ConPatIn c ps) acc = foldr collect_pat acc (hsConArgs ps) -collect_pat other acc = acc -- Literals, vars, wildcard +isBangHsBind :: HsBind id -> Bool +-- In this module because HsPat is above HsBinds in the import graph +isBangHsBind (PatBind { pat_lhs = L _ (BangPat p) }) = True +isBangHsBind bind = False + +isIrrefutableHsPat :: LPat id -> Bool +-- This function returns False if it's in doubt; specifically +-- on a ConPatIn it doesn't know the size of the constructor family +-- But if it returns True, the pattern is definitely irrefutable +isIrrefutableHsPat pat + = go pat + where + go (L _ pat) = go1 pat + + go1 (WildPat _) = True + go1 (VarPat _) = True + go1 (VarPatOut _ _) = True + go1 (LazyPat pat) = True + go1 (BangPat pat) = go pat + go1 (ParPat pat) = go pat + go1 (AsPat _ pat) = go pat + go1 (SigPatIn pat _) = go pat + go1 (SigPatOut pat _) = go pat + go1 (TuplePat pats _ _) = all go pats + go1 (ListPat pats _) = False + go1 (PArrPat pats _) = False -- ? + + go1 (ConPatIn _ _) = False -- Conservative + go1 (ConPatOut (L _ con) _ _ _ details _) + = isProductTyCon (dataConTyCon con) + && all go (hsConArgs details) + + go1 (LitPat _) = False + go1 (NPat _ _ _ _) = False + go1 (NPlusKPat _ _ _ _) = False + + go1 (TypePat _) = panic "isIrrefutableHsPat: type pattern" + go1 (DictPat _ _) = panic "isIrrefutableHsPat: type pattern" \end{code}