X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=af921de689221cfa825a35f55b3946a744ca204f;hb=fb6d198f498d4e325a540f28aaa6e1d1530839c3;hp=b21f1166640c995e29ca96e9cdb4f2ab6d0bb4ef;hpb=28ae38a309c6484c3ba1b4658277c32d71eadaaa;p=ghc-hetmet.git diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs index b21f116..af921de 100644 --- a/compiler/hsSyn/HsPat.lhs +++ b/compiler/hsSyn/HsPat.lhs @@ -5,6 +5,13 @@ \section[PatSyntax]{Abstract Haskell syntax---patterns} \begin{code} +{-# OPTIONS -fno-warn-incomplete-patterns #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module HsPat ( Pat(..), InPat, OutPat, LPat, @@ -12,17 +19,16 @@ module HsPat ( HsConPatDetails, hsConPatArgs, HsRecFields(..), HsRecField(..), hsRecFields, - mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, + HsQuasiQuote(..), + + mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, mkCoPatCoI, - isBangHsBind, + isBangHsBind, hsPatNeedsParens, patsAreAllCons, isConPat, isSigPat, isWildPat, patsAreAllLits, isLitPat, isIrrefutableHsPat ) where -#include "HsVersions.h" - - -import {-# SOURCE #-} HsExpr ( SyntaxExpr ) +import {-# SOURCE #-} HsExpr (SyntaxExpr, LHsExpr, pprLExpr) -- friends: import HsBinds @@ -30,6 +36,7 @@ import HsLit import HsTypes import BasicTypes -- others: +import Coercion import PprCore ( {- instance OutputableBndr TyVar -} ) import TysWiredIn import Var @@ -38,6 +45,7 @@ import TyCon import Outputable import Type import SrcLoc +import FastString \end{code} @@ -59,7 +67,7 @@ data Pat id | LazyPat (LPat id) -- Lazy pattern | AsPat (Located id) (LPat id) -- As pattern | ParPat (LPat id) -- Parenthesised pattern - | BangPat (LPat id) -- Bang patterng + | BangPat (LPat id) -- Bang pattern ------------ Lists, tuples, arrays --------------- | ListPat [LPat id] -- Syntactic list @@ -89,14 +97,26 @@ data Pat id | ConPatOut { pat_con :: Located DataCon, - pat_tvs :: [TyVar], -- Existentially bound type variables - -- including any bound coercion variables - pat_dicts :: [id], -- Ditto dictionaries + pat_tvs :: [TyVar], -- Existentially bound type variables (tyvars only) + pat_dicts :: [id], -- Ditto *coercion variables* and *dictionaries* + -- One reason for putting coercion variable here, I think, + -- is to ensure their kinds are zonked pat_binds :: DictBinds id, -- Bindings involving those dictionaries pat_args :: HsConPatDetails id, pat_ty :: Type -- The type of the pattern } + ------------ View patterns --------------- + | ViewPat (LHsExpr id) + (LPat id) + PostTcType -- The overall type of the pattern + -- (= the argument type of the view function) + -- for hsPatType. + + ------------ Quasiquoted patterns --------------- + -- See Note [Quasi-quote overview] in TcSplice + | QuasiQuotePat (HsQuasiQuote id) + ------------ Literal and n+k patterns --------------- | LitPat HsLit -- Used for *non-overloaded* literal patterns: -- Int#, Char#, Int, Char, String, etc. @@ -105,7 +125,6 @@ data Pat id (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 @@ -156,15 +175,23 @@ However HsRecFields is used only for patterns and expressions \begin{code} data HsRecFields id arg -- A bunch of record fields -- { x = 3, y = True } - -- Used for both expressiona and patterns + -- Used for both expressions and patterns = HsRecFields { rec_flds :: [HsRecField id arg], - rec_dotdot :: Maybe Int } - -- Nothing => the normal case - -- Just n => the group uses ".." notation, - -- and the first n elts of rec_flds - -- were the user-written ones - -- (In the latter case, the remaining elts of - -- rec_flds are the non-user-written ones) + rec_dotdot :: Maybe Int } -- Note [DotDot fields] + +-- Note [DotDot fields] +-- ~~~~~~~~~~~~~~~~~~~~ +-- The rec_dotdot field means this: +-- Nothing => the normal case +-- Just n => the group uses ".." notation, +-- +-- In the latter case: +-- +-- *before* renamer: rec_flds are exactly the n user-written fields +-- +-- *after* renamer: rec_flds includes *all* fields, with +-- the first 'n' being the user-written ones +-- and the remainder being 'filled in' implicitly data HsRecField id arg = HsRecField { hsRecFieldId :: Located id, @@ -177,14 +204,34 @@ data HsRecField id arg = HsRecField { -- If you write T { x, y = v+1 }, the HsRecFields will be -- HsRecField x x True ... -- HsRecField y (v+1) False ... --- That is, for "punned" field x is immediately expanded to x=x --- but with a punning flag so we can detect it later +-- That is, for "punned" field x is expanded (in the renamer) +-- to x=x; but with a punning flag so we can detect it later -- (e.g. when pretty printing) +-- +-- If the original field was qualified, we un-qualify it, thus +-- T { A.x } means T { A.x = x } hsRecFields :: HsRecFields id arg -> [id] hsRecFields rbinds = map (unLoc . hsRecFieldId) (rec_flds rbinds) \end{code} +\begin{code} +data HsQuasiQuote id = HsQuasiQuote + id + id + SrcSpan + FastString + +instance OutputableBndr id => Outputable (HsQuasiQuote id) where + ppr = ppr_qq + +ppr_qq :: OutputableBndr id => HsQuasiQuote id -> SDoc +ppr_qq (HsQuasiQuote name quoter _ quote) = + char '$' <> brackets (ppr name) <> + ptext (sLit "[:") <> ppr quoter <> ptext (sLit "|") <> + ppr quote <> ptext (sLit "|]") +\end{code} + %************************************************************************ %* * @@ -212,7 +259,8 @@ pprPat (WildPat _) = char '_' pprPat (LazyPat pat) = char '~' <> ppr pat pprPat (BangPat pat) = char '!' <> ppr pat pprPat (AsPat name pat) = parens (hcat [ppr name, char '@', ppr pat]) -pprPat (ParPat pat) = parens (ppr pat) +pprPat (ViewPat expr pat _) = parens (hcat [pprLExpr expr, text " -> ", ppr pat]) +pprPat (ParPat pat) = parens (ppr pat) pprPat (ListPat pats _) = brackets (interpp'SP pats) pprPat (PArrPat pats _) = pabrackets (interpp'SP pats) pprPat (TuplePat pats bx _) = tupleParens bx (interpp'SP pats) @@ -228,17 +276,23 @@ pprPat (ConPatOut { pat_con = con, pat_tvs = tvs, pat_dicts = dicts, else pprUserCon con details pprPat (LitPat s) = ppr s -pprPat (NPat l Nothing _ _) = ppr l -pprPat (NPat l (Just _) _ _) = char '-' <> ppr l +pprPat (NPat l Nothing _) = ppr l +pprPat (NPat l (Just _) _) = char '-' <> ppr l pprPat (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k] -pprPat (TypePat ty) = ptext SLIT("{|") <> ppr ty <> ptext SLIT("|}") +pprPat (QuasiQuotePat (HsQuasiQuote name quoter _ quote)) + = char '$' <> brackets (ppr name) <> + ptext (sLit "[:") <> ppr quoter <> ptext (sLit "|") <> + ppr quote <> ptext (sLit "|]") +pprPat (TypePat ty) = ptext (sLit "{|") <> ppr ty <> ptext (sLit "|}") pprPat (CoPat co pat _) = parens (pprHsWrapper (ppr pat) co) pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty pprPat (SigPatOut pat ty) = ppr pat <+> dcolon <+> ppr ty +pprUserCon :: (Outputable con, OutputableBndr id) => con -> HsConPatDetails id -> SDoc pprUserCon c (InfixCon p1 p2) = ppr p1 <+> ppr c <+> ppr p2 pprUserCon c details = ppr c <+> pprConArgs details +pprConArgs :: OutputableBndr id => HsConPatDetails id -> SDoc pprConArgs (PrefixCon pats) = interppSP pats pprConArgs (InfixCon p1 p2) = interppSP [p1,p2] pprConArgs (RecCon rpats) = ppr rpats @@ -250,18 +304,18 @@ instance (OutputableBndr id, Outputable arg) ppr (HsRecFields { rec_flds = flds, rec_dotdot = Just n }) = braces (fsep (punctuate comma (map ppr (take n flds) ++ [dotdot]))) where - dotdot = ptext SLIT("..") <+> ifPprDebug (ppr (drop n flds)) + dotdot = ptext (sLit "..") <+> ifPprDebug (ppr (drop n flds)) instance (OutputableBndr id, Outputable arg) => Outputable (HsRecField id arg) where ppr (HsRecField { hsRecFieldId = f, hsRecFieldArg = arg, hsRecPun = pun }) - = ppr f <+> (if pun then empty else equals <+> ppr arg) + = ppr f <+> (ppUnless pun $ equals <+> ppr arg) -- add parallel array brackets around a document -- pabrackets :: SDoc -> SDoc -pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") +pabrackets p = ptext (sLit "[:") <> p <> ptext (sLit ":]") \end{code} @@ -285,10 +339,14 @@ mkNilPat ty = mkPrefixConPat nilDataCon [] ty mkCharLitPat :: Char -> OutPat id mkCharLitPat c = mkPrefixConPat charDataCon [noLoc $ LitPat (HsCharPrim c)] charTy -mkCoPat :: HsWrapper -> OutPat id -> Type -> OutPat id -mkCoPat co lpat@(L loc pat) ty - | isIdHsWrapper co = lpat - | otherwise = L loc (CoPat co pat ty) +mkCoPat :: HsWrapper -> Pat id -> Type -> Pat id +mkCoPat co pat ty + | isIdHsWrapper co = pat + | otherwise = CoPat co pat ty + +mkCoPatCoI :: CoercionI -> Pat id -> Type -> Pat id +mkCoPatCoI IdCo pat _ = pat +mkCoPatCoI (ACo co) pat ty = mkCoPat (WpCast co) pat ty \end{code} @@ -322,70 +380,112 @@ patterns are treated specially, of course. The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are. \begin{code} +isWildPat :: Pat id -> Bool isWildPat (WildPat _) = True -isWildPat other = False +isWildPat _ = False patsAreAllCons :: [Pat id] -> Bool patsAreAllCons pat_list = all isConPat pat_list +isConPat :: Pat id -> Bool isConPat (AsPat _ pat) = isConPat (unLoc pat) isConPat (ConPatIn {}) = True isConPat (ConPatOut {}) = True isConPat (ListPat {}) = True isConPat (PArrPat {}) = True isConPat (TuplePat {}) = True -isConPat other = False +isConPat _ = False +isSigPat :: Pat id -> Bool isSigPat (SigPatIn _ _) = True isSigPat (SigPatOut _ _) = True -isSigPat other = False +isSigPat _ = False patsAreAllLits :: [Pat id] -> Bool patsAreAllLits pat_list = all isLitPat pat_list +isLitPat :: Pat id -> Bool isLitPat (AsPat _ pat) = isLitPat (unLoc pat) isLitPat (LitPat _) = True -isLitPat (NPat _ _ _ _) = True +isLitPat (NPat _ _ _) = True isLitPat (NPlusKPat _ _ _ _) = True -isLitPat other = False +isLitPat _ = False 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 +isBangHsBind (PatBind { pat_lhs = L _ (BangPat _) }) = True +isBangHsBind _ = False + +isIrrefutableHsPat :: OutputableBndr id => LPat id -> Bool +-- (isIrrefutableHsPat p) is true if matching against p cannot fail, +-- in the sense of falling through to the next pattern. +-- (NB: this is not quite the same as the (silly) defn +-- in 3.17.2 of the Haskell 98 report.) +-- +-- isIrrefutableHsPat 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 + go (L _ pat) = go1 pat - go1 (WildPat _) = True - go1 (VarPat _) = True - go1 (VarPatOut _ _) = True - go1 (LazyPat pat) = True + go1 (WildPat {}) = True + go1 (VarPat {}) = True + go1 (VarPatOut {}) = True + go1 (LazyPat {}) = True go1 (BangPat pat) = go pat go1 (CoPat _ pat _) = go1 pat go1 (ParPat pat) = go pat go1 (AsPat _ pat) = go pat + go1 (ViewPat _ 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 (ListPat {}) = False + go1 (PArrPat {}) = False -- ? - go1 (ConPatIn _ _) = False -- Conservative + go1 (ConPatIn {}) = False -- Conservative go1 (ConPatOut{ pat_con = L _ con, pat_args = details }) = isProductTyCon (dataConTyCon con) && all go (hsConPatArgs details) - go1 (LitPat _) = False - go1 (NPat _ _ _ _) = False - go1 (NPlusKPat _ _ _ _) = False - - go1 (TypePat _) = panic "isIrrefutableHsPat: type pattern" + go1 (LitPat {}) = False + go1 (NPat {}) = False + go1 (NPlusKPat {}) = False + + go1 (QuasiQuotePat {}) = urk pat -- Gotten rid of by renamer, before + -- isIrrefutablePat is called + go1 (TypePat {}) = urk pat + + urk pat = pprPanic "isIrrefutableHsPat:" (ppr pat) + +hsPatNeedsParens :: Pat a -> Bool +hsPatNeedsParens (WildPat {}) = False +hsPatNeedsParens (VarPat {}) = False +hsPatNeedsParens (VarPatOut {}) = True +hsPatNeedsParens (LazyPat {}) = False +hsPatNeedsParens (BangPat {}) = False +hsPatNeedsParens (CoPat {}) = True +hsPatNeedsParens (ParPat {}) = False +hsPatNeedsParens (AsPat {}) = False +hsPatNeedsParens (ViewPat {}) = True +hsPatNeedsParens (SigPatIn {}) = True +hsPatNeedsParens (SigPatOut {}) = True +hsPatNeedsParens (TuplePat {}) = False +hsPatNeedsParens (ListPat {}) = False +hsPatNeedsParens (PArrPat {}) = False +hsPatNeedsParens (ConPatIn _ ds) = conPatNeedsParens ds +hsPatNeedsParens (ConPatOut {}) = True +hsPatNeedsParens (LitPat {}) = False +hsPatNeedsParens (NPat {}) = False +hsPatNeedsParens (NPlusKPat {}) = True +hsPatNeedsParens (QuasiQuotePat {}) = True +hsPatNeedsParens (TypePat {}) = False + +conPatNeedsParens :: HsConDetails a b -> Bool +conPatNeedsParens (PrefixCon args) = not (null args) +conPatNeedsParens (InfixCon {}) = False +conPatNeedsParens (RecCon {}) = False \end{code}