X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsExpr.lhs;h=883015549a18ea09a6ddcbce1c4fee0f63367717;hp=18306a98de67e3fafd496f2c488eee4b2bb8aad9;hb=a8427a4125e9b78e88a487eeabf018f1c6e8bc08;hpb=15cb792d18b1094e98c035dca6ecec5dad516056 diff --git a/compiler/hsSyn/HsExpr.lhs b/compiler/hsSyn/HsExpr.lhs index 18306a9..8830155 100644 --- a/compiler/hsSyn/HsExpr.lhs +++ b/compiler/hsSyn/HsExpr.lhs @@ -1,7 +1,9 @@ % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % -\section[HsExpr]{Abstract Haskell syntax: expressions} + +HsExpr: Abstract Haskell syntax: expressions \begin{code} module HsExpr where @@ -9,20 +11,19 @@ module HsExpr where #include "HsVersions.h" -- friends: -import HsDecls ( HsGroup ) -import HsPat ( LPat ) -import HsLit ( HsLit(..), HsOverLit ) -import HsTypes ( LHsType, PostTcType ) -import HsImpExp ( isOperator, pprHsVar ) -import HsBinds ( HsLocalBinds, DictBinds, isEmptyLocalBinds, - ExprCoFn, pprCoFn ) +import HsDecls +import HsPat +import HsLit +import HsTypes +import HsImpExp +import HsBinds -- others: -import Type ( Type, pprParendType ) -import Var ( TyVar, Id ) -import Name ( Name ) -import BasicTypes ( IPName, Boxity, tupleParens, Arity, Fixity(..) ) -import SrcLoc ( Located(..), unLoc ) +import Var +import Name +import BasicTypes +import DataCon +import SrcLoc import Outputable import FastString \end{code} @@ -158,9 +159,11 @@ data HsExpr id -- Record update | RecordUpd (LHsExpr id) (HsRecordBinds id) - PostTcType -- Type of *input* record - PostTcType -- Type of *result* record (may differ from - -- type of input record) + [DataCon] -- Filled in by the type checker to the *non-empty* + -- list of DataCons that have all the upd'd fields + [PostTcType] -- Argument types of *input* record type + [PostTcType] -- and *output* record type + -- For a type family, the arg types are of the *instance* tycon, not the family tycon | ExprWithTySig -- e :: type (LHsExpr id) @@ -186,6 +189,7 @@ data HsExpr id ----------------------------------------------------------- -- MetaHaskell Extensions + | HsBracket (HsBracket id) | HsBracketOut (HsBracket Name) -- Output of the type checker is the *original* @@ -220,13 +224,29 @@ data HsExpr id (Maybe Fixity) -- fixity (filled in by the renamer), for forms that -- were converted from OpApp's by the renamer [LHsCmdTop id] -- argument commands -\end{code} -These constructors only appear temporarily in the parser. -The renamer translates them into the Right Thing. + --------------------------------------- + -- Haskell program coverage (Hpc) Support + + | HsTick + Int -- module-local tick number + [id] -- variables in scope + (LHsExpr id) -- sub-expression + + | HsBinTick + Int -- module-local tick number for True + Int -- module-local tick number for False + (LHsExpr id) -- sub-expression + + | HsTickPragma -- A pragma introduced tick + (FastString,(Int,Int),(Int,Int)) -- external span for this tick + (LHsExpr id) + + --------------------------------------- + -- These constructors only appear temporarily in the parser. + -- The renamer translates them into the Right Thing. -\begin{code} | EWildPat -- wildcard | EAsPat (Located id) -- as pattern @@ -235,12 +255,11 @@ The renamer translates them into the Right Thing. | ELazyPat (LHsExpr id) -- ~ pattern | HsType (LHsType id) -- Explicit type argument; e.g f {| Int |} x y -\end{code} -Everything from here on appears only in typechecker output. + --------------------------------------- + -- Finally, HsWrap appears only in typechecker output -\begin{code} - | HsCoerce ExprCoFn -- TRANSLATION + | HsWrap HsWrapper -- TRANSLATION (HsExpr id) type PendingSplice = (Name, LHsExpr Id) -- Typechecked splices, waiting to be @@ -259,13 +278,30 @@ instance OutputableBndr id => Outputable (HsExpr id) where \end{code} \begin{code} -pprExpr :: OutputableBndr id => HsExpr id -> SDoc +----------------------- +-- pprExpr, pprLExpr, pprBinds call pprDeeper; +-- the underscore versions do not +pprLExpr :: OutputableBndr id => LHsExpr id -> SDoc +pprLExpr (L _ e) = pprExpr e -pprExpr e = pprDeeper (ppr_expr e) +pprExpr :: OutputableBndr id => HsExpr id -> SDoc +pprExpr e | isAtomicHsExpr e || isQuietHsExpr e = ppr_expr e + | otherwise = pprDeeper (ppr_expr e) + +isQuietHsExpr :: HsExpr id -> Bool +-- Parentheses do display something, but it gives little info and +-- if we go deeper when we go inside them then we get ugly things +-- like (...) +isQuietHsExpr (HsPar _) = True +-- applications don't display anything themselves +isQuietHsExpr (HsApp _ _) = True +isQuietHsExpr (OpApp _ _ _ _) = True +isQuietHsExpr _ = False pprBinds :: OutputableBndr id => HsLocalBinds id -> SDoc pprBinds b = pprDeeper (ppr b) +----------------------- ppr_lexpr :: OutputableBndr id => LHsExpr id -> SDoc ppr_lexpr e = ppr_expr (unLoc e) @@ -290,8 +326,8 @@ ppr_expr (OpApp e1 op fixity e2) HsVar v -> pp_infixly v _ -> pp_prefixly where - pp_e1 = pprParendExpr e1 -- Add parens to make precedence clear - pp_e2 = pprParendExpr e2 + pp_e1 = pprDebugParendExpr e1 -- In debug mode, add parens + pp_e2 = pprDebugParendExpr e2 -- to make precedence clear pp_prefixly = hang (ppr op) 2 (sep [pp_e1, pp_e2]) @@ -299,14 +335,14 @@ ppr_expr (OpApp e1 op fixity e2) pp_infixly v = sep [nest 2 pp_e1, pprInfix v, nest 2 pp_e2] -ppr_expr (NegApp e _) = char '-' <+> pprParendExpr e +ppr_expr (NegApp e _) = char '-' <+> pprDebugParendExpr e ppr_expr (SectionL expr op) = case unLoc op of HsVar v -> pp_infixly v _ -> pp_prefixly where - pp_expr = pprParendExpr expr + pp_expr = pprDebugParendExpr expr pp_prefixly = hang (hsep [text " \\ x_ ->", ppr op]) 4 (hsep [pp_expr, ptext SLIT("x_ )")]) @@ -317,7 +353,7 @@ ppr_expr (SectionR op expr) HsVar v -> pp_infixly v _ -> pp_prefixly where - pp_expr = pprParendExpr expr + pp_expr = pprDebugParendExpr expr pp_prefixly = hang (hsep [text "( \\ x_ ->", ppr op, ptext SLIT("x_")]) 4 ((<>) pp_expr rparen) @@ -349,19 +385,19 @@ ppr_expr (HsLet binds expr) ppr_expr (HsDo do_or_list_comp stmts body _) = pprDo do_or_list_comp stmts body ppr_expr (ExplicitList _ exprs) - = brackets (fsep (punctuate comma (map ppr_lexpr exprs))) + = brackets (pprDeeperList fsep (punctuate comma (map ppr_lexpr exprs))) ppr_expr (ExplicitPArr _ exprs) - = pa_brackets (fsep (punctuate comma (map ppr_lexpr exprs))) + = pa_brackets (pprDeeperList fsep (punctuate comma (map ppr_lexpr exprs))) ppr_expr (ExplicitTuple exprs boxity) = tupleParens boxity (sep (punctuate comma (map ppr_lexpr exprs))) ppr_expr (RecordCon con_id con_expr rbinds) - = pp_rbinds (ppr con_id) rbinds + = hang (ppr con_id) 2 (ppr rbinds) -ppr_expr (RecordUpd aexp rbinds _ _) - = pp_rbinds (pprParendExpr aexp) rbinds +ppr_expr (RecordUpd aexp rbinds _ _ _) + = hang (pprParendExpr aexp) 2 (ppr rbinds) ppr_expr (ExprWithTySig expr sig) = hang (nest 2 (ppr_lexpr expr) <+> dcolon) @@ -380,7 +416,7 @@ ppr_expr (EAsPat v e) = ppr v <> char '@' <> pprParendExpr e ppr_expr (HsSCC lbl expr) = sep [ ptext SLIT("_scc_") <+> doubleQuotes (ftext lbl), pprParendExpr expr ] -ppr_expr (HsCoerce co_fn e) = pprCoFn (ppr_expr e) co_fn +ppr_expr (HsWrap co_fn e) = pprHsWrapper (pprExpr e) co_fn ppr_expr (HsType id) = ppr id ppr_expr (HsSpliceE s) = pprSplice s @@ -391,6 +427,18 @@ ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("pending") <+> ppr ps ppr_expr (HsProc pat (L _ (HsCmdTop cmd _ _ _))) = hsep [ptext SLIT("proc"), ppr pat, ptext SLIT("->"), ppr cmd] +ppr_expr (HsTick tickId vars exp) + = hcat [ptext SLIT("tick<"), ppr tickId,ptext SLIT(">("), hsep (map pprHsVar vars), ppr exp,ptext SLIT(")")] +ppr_expr (HsBinTick tickIdTrue tickIdFalse exp) + = hcat [ptext SLIT("bintick<"), + ppr tickIdTrue, + ptext SLIT(","), + ppr tickIdFalse, + ptext SLIT(">("), + ppr exp,ptext SLIT(")")] +ppr_expr (HsTickPragma externalSrcLoc exp) + = hcat [ptext SLIT("tickpragma<"), ppr externalSrcLoc,ptext SLIT(">("), ppr exp,ptext SLIT(")")] + ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp True) = hsep [ppr_lexpr arrow, ptext SLIT("-<"), ppr_lexpr arg] ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp False) @@ -425,29 +473,53 @@ pa_brackets :: SDoc -> SDoc pa_brackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") \end{code} -Parenthesize unless very simple: +HsSyn records exactly where the user put parens, with HsPar. +So generally speaking we print without adding any parens. +However, some code is internally generated, and in some places +parens are absolutely required; so for these places we use +pprParendExpr (but don't print double parens of course). + +For operator applications we don't add parens, because the oprerator +fixities should do the job, except in debug mode (-dppr-debug) so we +can see the structure of the parse tree. + \begin{code} +pprDebugParendExpr :: OutputableBndr id => LHsExpr id -> SDoc +pprDebugParendExpr expr + = getPprStyle (\sty -> + if debugStyle sty then pprParendExpr expr + else pprLExpr expr) + pprParendExpr :: OutputableBndr id => LHsExpr id -> SDoc pprParendExpr expr = let - pp_as_was = ppr_lexpr expr - -- Using ppr_expr here avoids the call to 'deeper' - -- Not sure if that's always right. + pp_as_was = pprLExpr expr + -- Using pprLExpr makes sure that we go 'deeper' + -- I think that is usually (always?) right in case unLoc expr of - HsLit l -> ppr l - HsOverLit l -> ppr l - - HsVar _ -> pp_as_was - HsIPVar _ -> pp_as_was - ExplicitList _ _ -> pp_as_was - ExplicitPArr _ _ -> pp_as_was - ExplicitTuple _ _ -> pp_as_was - HsPar _ -> pp_as_was - HsBracket _ -> pp_as_was - HsBracketOut _ [] -> pp_as_was - - _ -> parens pp_as_was + HsLit l -> pp_as_was + HsOverLit l -> pp_as_was + HsVar _ -> pp_as_was + HsIPVar _ -> pp_as_was + ExplicitList _ _ -> pp_as_was + ExplicitPArr _ _ -> pp_as_was + ExplicitTuple _ _ -> pp_as_was + HsPar _ -> pp_as_was + HsBracket _ -> pp_as_was + HsBracketOut _ [] -> pp_as_was + HsDo sc _ _ _ + | isListCompExpr sc -> pp_as_was + _ -> parens pp_as_was + +isAtomicHsExpr :: HsExpr id -> Bool -- A single token +isAtomicHsExpr (HsVar {}) = True +isAtomicHsExpr (HsLit {}) = True +isAtomicHsExpr (HsOverLit {}) = True +isAtomicHsExpr (HsIPVar {}) = True +isAtomicHsExpr (HsWrap _ e) = isAtomicHsExpr e +isAtomicHsExpr (HsPar e) = isAtomicHsExpr (unLoc e) +isAtomicHsExpr e = False \end{code} %************************************************************************ @@ -527,17 +599,7 @@ data HsCmdTop id %************************************************************************ \begin{code} -type HsRecordBinds id = [(Located id, LHsExpr id)] - -recBindFields :: HsRecordBinds id -> [id] -recBindFields rbinds = [unLoc field | (field,_) <- rbinds] - -pp_rbinds :: OutputableBndr id => SDoc -> HsRecordBinds id -> SDoc -pp_rbinds thing rbinds - = hang thing - 4 (braces (sep (punctuate comma (map (pp_rbind) rbinds)))) - where - pp_rbind (v, e) = hsep [pprBndr LetBind (unLoc v), char '=', ppr e] +type HsRecordBinds id = HsRecFields id (LHsExpr id) \end{code} @@ -607,11 +669,13 @@ We know the list must have at least one @Match@ in it. \begin{code} pprMatches :: (OutputableBndr id) => HsMatchContext id -> MatchGroup id -> SDoc -pprMatches ctxt (MatchGroup matches ty) = (ppr ty) $$ vcat (map (pprMatch ctxt) (map unLoc matches)) +pprMatches ctxt (MatchGroup matches ty) = vcat (map (pprMatch ctxt) (map unLoc matches)) + -- Don't print the type; it's only + -- a place-holder before typechecking -- Exported to HsBinds, which can't see the defn of HsMatchContext -pprFunBind :: (OutputableBndr id) => id -> MatchGroup id -> SDoc -pprFunBind fun matches = pprMatches (FunRhs fun) matches +pprFunBind :: (OutputableBndr id) => id -> Bool -> MatchGroup id -> SDoc +pprFunBind fun inf matches = pprMatches (FunRhs fun inf) matches -- Exported to HsBinds, which can't see the defn of HsMatchContext pprPatBind :: (OutputableBndr bndr, OutputableBndr id) @@ -621,14 +685,29 @@ pprPatBind pat grhss = sep [ppr pat, nest 4 (pprGRHSs PatBindRhs grhss)] pprMatch :: OutputableBndr id => HsMatchContext id -> Match id -> SDoc pprMatch ctxt (Match pats maybe_ty grhss) - = pp_name ctxt <+> sep [sep (map ppr pats), - ppr_maybe_ty, - nest 2 (pprGRHSs ctxt grhss)] + = herald <+> sep [sep (map ppr other_pats), + ppr_maybe_ty, + nest 2 (pprGRHSs ctxt grhss)] where - pp_name (FunRhs fun) = ppr fun -- Not pprBndr; the AbsBinds will - -- have printed the signature - pp_name LambdaExpr = char '\\' - pp_name other = empty + (herald, other_pats) + = case ctxt of + FunRhs fun is_infix + | not is_infix -> (ppr fun, pats) + -- f x y z = e + -- Not pprBndr; the AbsBinds will + -- have printed the signature + + | null pats3 -> (pp_infix, []) + -- x &&& y = e + + | otherwise -> (parens pp_infix, pats3) + -- (x &&& y) z = e + where + (pat1:pat2:pats3) = pats + pp_infix = ppr pat1 <+> ppr fun <+> ppr pat2 + + LambdaExpr -> (char '\\', pats) + other -> (empty, pats) ppr_maybe_ty = case maybe_ty of Just ty -> dcolon <+> ppr ty @@ -638,9 +717,8 @@ pprMatch ctxt (Match pats maybe_ty grhss) pprGRHSs :: OutputableBndr id => HsMatchContext id -> GRHSs id -> SDoc pprGRHSs ctxt (GRHSs grhss binds) = vcat (map (pprGRHS ctxt . unLoc) grhss) - $$ - (if isEmptyLocalBinds binds then empty - else text "where" $$ nest 4 (pprBinds binds)) + $$ if isEmptyLocalBinds binds then empty + else text "where" $$ nest 4 (pprBinds binds) pprGRHS :: OutputableBndr id => HsMatchContext id -> GRHS id -> SDoc @@ -762,8 +840,8 @@ pprStmt (ParStmt stmtss) = hsep (map (\stmts -> ptext SLIT("| ") <> ppr pprStmt (RecStmt segment _ _ _ _) = ptext SLIT("rec") <+> braces (vcat (map ppr segment)) pprDo :: OutputableBndr id => HsStmtContext any -> [LStmt id] -> LHsExpr id -> SDoc -pprDo DoExpr stmts body = ptext SLIT("do") <+> (vcat (map ppr stmts) $$ ppr body) -pprDo (MDoExpr _) stmts body = ptext SLIT("mdo") <+> (vcat (map ppr stmts) $$ ppr body) +pprDo DoExpr stmts body = ptext SLIT("do") <+> pprDeeperList vcat (map ppr stmts ++ [ppr body]) +pprDo (MDoExpr _) stmts body = ptext SLIT("mdo") <+> pprDeeperList vcat (map ppr stmts ++ [ppr body]) pprDo ListComp stmts body = pprComp brackets stmts body pprDo PArrComp stmts body = pprComp pa_brackets stmts body pprDo other stmts body = panic "pprDo" -- PatGuard, ParStmtCxt @@ -855,7 +933,7 @@ pp_dotdot = ptext SLIT(" .. ") \begin{code} data HsMatchContext id -- Context of a Match - = FunRhs id -- Function binding for f + = FunRhs id Bool -- Function binding for f; True <=> written infix | CaseAlt -- Guard on a case alternative | LambdaExpr -- Pattern of a lambda | ProcExpr -- Pattern of a proc @@ -880,11 +958,16 @@ data HsStmtContext id isDoExpr :: HsStmtContext id -> Bool isDoExpr DoExpr = True isDoExpr (MDoExpr _) = True -isDoExpr other = False +isDoExpr _ = False + +isListCompExpr :: HsStmtContext id -> Bool +isListCompExpr ListComp = True +isListCompExpr PArrComp = True +isListCompExpr _ = False \end{code} \begin{code} -matchSeparator (FunRhs _) = ptext SLIT("=") +matchSeparator (FunRhs {}) = ptext SLIT("=") matchSeparator CaseAlt = ptext SLIT("->") matchSeparator LambdaExpr = ptext SLIT("->") matchSeparator ProcExpr = ptext SLIT("->") @@ -894,7 +977,7 @@ matchSeparator RecUpd = panic "unused" \end{code} \begin{code} -pprMatchContext (FunRhs fun) = ptext SLIT("the definition of") <+> quotes (ppr fun) +pprMatchContext (FunRhs fun _) = ptext SLIT("the definition of") <+> quotes (ppr fun) pprMatchContext CaseAlt = ptext SLIT("a case alternative") pprMatchContext RecUpd = ptext SLIT("a record-update construct") pprMatchContext PatBindRhs = ptext SLIT("a pattern binding") @@ -925,7 +1008,7 @@ pprStmtResultContext other = ptext SLIT("the result of") <+> pprStmtContext -} -- Used to generate the string for a *runtime* error message -matchContextErrString (FunRhs fun) = "function " ++ showSDoc (ppr fun) +matchContextErrString (FunRhs fun _) = "function " ++ showSDoc (ppr fun) matchContextErrString CaseAlt = "case" matchContextErrString PatBindRhs = "pattern binding" matchContextErrString RecUpd = "record update"