\begin{code}
module RnExpr (
- rnMatch, rnGRHSs, rnPat, rnExpr, rnExprs,
- rnStmt, rnStmts, checkPrecMatch
+ rnMatch, rnGRHSs, rnExpr, rnExprs, rnStmts,
+ checkPrecMatch
) where
#include "HsVersions.h"
-import {-# SOURCE #-} RnSource ( rnSrcDecls, rnBinds )
+import {-# SOURCE #-} RnSource ( rnSrcDecls, rnBindsAndThen, rnBinds )
+
+-- RnSource imports RnBinds.rnTopMonoBinds, RnExpr.rnExpr
+-- RnBinds imports RnExpr.rnMatch, etc
+-- RnExpr imports [boot] RnSource.rnSrcDecls, RnSource.rnBinds
import HsSyn
import RdrHsSyn
import RnHsSyn
import TcRnMonad
import RnEnv
-import RnTypes ( rnHsTypeFVs, precParseErr, sectionPrecErr )
+import RnNames ( importsFromLocalDecls )
+import RnTypes ( rnHsTypeFVs, rnPat, litFVs, rnOverLit, rnPatsAndThen,
+ dupFieldErr, precParseErr, sectionPrecErr, patSigErr, checkTupSize )
import CmdLineOpts ( DynFlag(..), opt_IgnoreAsserts )
-import Literal ( inIntRange, inCharRange )
import BasicTypes ( Fixity(..), FixityDirection(..), IPName(..),
defaultFixity, negateFixity, compareFixity )
import PrelNames ( hasKey, assertIdKey,
- eqClassName, foldrName, buildName, eqStringName,
+ foldrName, buildName,
cCallableClassName, cReturnableClassName,
- enumClassName, ordClassName,
- ratioDataConName, splitName, fstName, sndName,
- ioDataConName, plusIntegerName, timesIntegerName,
+ enumClassName,
+ loopAName, choiceAName, appAName, arrAName, composeAName, firstAName,
+ splitName, fstName, sndName, ioDataConName,
replicatePName, mapPName, filterPName,
- crossPName, zipPName, lengthPName, indexPName, toPName,
+ crossPName, zipPName, toPName,
enumFromToPName, enumFromThenToPName, assertErrorName,
- fromIntegerName, fromRationalName, minusName, negateName,
- qTyConName, monadNames )
-import TysPrim ( charPrimTyCon, addrPrimTyCon, intPrimTyCon,
- floatPrimTyCon, doublePrimTyCon )
-import TysWiredIn ( intTyCon )
-import RdrName ( RdrName )
-import Name ( Name, NamedThing(..), mkSystemName, nameSrcLoc, nameOccName )
+ negateName, monadNames, mfixName )
+import Name ( Name, nameOccName )
import NameSet
import UnicodeUtil ( stringToUtf8 )
import UniqFM ( isNullUFM )
import UniqSet ( emptyUniqSet )
-import List ( intersectBy )
+import Util ( isSingleton, mapAndUnzip )
+import List ( intersectBy, unzip4 )
import ListSetOps ( removeDups )
import Outputable
+import SrcLoc ( noSrcLoc )
import FastString
\end{code}
-*********************************************************
-* *
-\subsection{Patterns}
-* *
-*********************************************************
-
-\begin{code}
-rnPat :: RdrNamePat -> RnM (RenamedPat, FreeVars)
-
-rnPat (WildPat _) = returnM (WildPat placeHolderType, emptyFVs)
-
-rnPat (VarPat name)
- = lookupBndrRn name `thenM` \ vname ->
- returnM (VarPat vname, emptyFVs)
-
-rnPat (SigPatIn pat ty)
- = doptM Opt_GlasgowExts `thenM` \ glaExts ->
-
- if glaExts
- then rnPat pat `thenM` \ (pat', fvs1) ->
- rnHsTypeFVs doc ty `thenM` \ (ty', fvs2) ->
- returnM (SigPatIn pat' ty', fvs1 `plusFV` fvs2)
-
- else addErr (patSigErr ty) `thenM_`
- rnPat pat
- where
- doc = text "In a pattern type-signature"
-
-rnPat (LitPat s@(HsString _))
- = returnM (LitPat s, unitFV eqStringName)
-
-rnPat (LitPat lit)
- = litFVs lit `thenM` \ fvs ->
- returnM (LitPat lit, fvs)
-
-rnPat (NPatIn lit mb_neg)
- = rnOverLit lit `thenM` \ (lit', fvs1) ->
- (case mb_neg of
- Nothing -> returnM (Nothing, emptyFVs)
- Just _ -> lookupSyntaxName negateName `thenM` \ (neg, fvs) ->
- returnM (Just neg, fvs)
- ) `thenM` \ (mb_neg', fvs2) ->
- returnM (NPatIn lit' mb_neg',
- fvs1 `plusFV` fvs2 `addOneFV` eqClassName)
- -- Needed to find equality on pattern
-
-rnPat (NPlusKPatIn name lit _)
- = rnOverLit lit `thenM` \ (lit', fvs1) ->
- lookupBndrRn name `thenM` \ name' ->
- lookupSyntaxName minusName `thenM` \ (minus, fvs2) ->
- returnM (NPlusKPatIn name' lit' minus,
- fvs1 `plusFV` fvs2 `addOneFV` ordClassName)
-
-rnPat (LazyPat pat)
- = rnPat pat `thenM` \ (pat', fvs) ->
- returnM (LazyPat pat', fvs)
-
-rnPat (AsPat name pat)
- = rnPat pat `thenM` \ (pat', fvs) ->
- lookupBndrRn name `thenM` \ vname ->
- returnM (AsPat vname pat', fvs)
-
-rnPat (ConPatIn con stuff) = rnConPat con stuff
-
-
-rnPat (ParPat pat)
- = rnPat pat `thenM` \ (pat', fvs) ->
- returnM (ParPat pat', fvs)
-
-rnPat (ListPat pats _)
- = mapFvRn rnPat pats `thenM` \ (patslist, fvs) ->
- returnM (ListPat patslist placeHolderType, fvs `addOneFV` listTyCon_name)
-
-rnPat (PArrPat pats _)
- = mapFvRn rnPat pats `thenM` \ (patslist, fvs) ->
- returnM (PArrPat patslist placeHolderType,
- fvs `plusFV` implicit_fvs `addOneFV` parrTyCon_name)
- where
- implicit_fvs = mkFVs [lengthPName, indexPName]
-
-rnPat (TuplePat pats boxed)
- = mapFvRn rnPat pats `thenM` \ (patslist, fvs) ->
- returnM (TuplePat patslist boxed, fvs `addOneFV` tycon_name)
- where
- tycon_name = tupleTyCon_name boxed (length pats)
-
-rnPat (TypePat name) =
- rnHsTypeFVs (text "In a type pattern") name `thenM` \ (name', fvs) ->
- returnM (TypePat name', fvs)
-
-------------------------------
-rnConPat con (PrefixCon pats)
- = lookupOccRn con `thenM` \ con' ->
- mapFvRn rnPat pats `thenM` \ (pats', fvs) ->
- returnM (ConPatIn con' (PrefixCon pats'), fvs `addOneFV` con')
-
-rnConPat con (RecCon rpats)
- = lookupOccRn con `thenM` \ con' ->
- rnRpats rpats `thenM` \ (rpats', fvs) ->
- returnM (ConPatIn con' (RecCon rpats'), fvs `addOneFV` con')
-
-rnConPat con (InfixCon pat1 pat2)
- = lookupOccRn con `thenM` \ con' ->
- rnPat pat1 `thenM` \ (pat1', fvs1) ->
- rnPat pat2 `thenM` \ (pat2', fvs2) ->
-
- getModeRn `thenM` \ mode ->
- -- See comments with rnExpr (OpApp ...)
- (if isInterfaceMode mode
- then returnM (ConPatIn con' (InfixCon pat1' pat2'))
- else lookupFixityRn con' `thenM` \ fixity ->
- mkConOpPatRn con' fixity pat1' pat2'
- ) `thenM` \ pat' ->
- returnM (pat', fvs1 `plusFV` fvs2 `addOneFV` con')
-\end{code}
-
-
************************************************************************
* *
\subsection{Match}
************************************************************************
\begin{code}
-rnMatch :: HsMatchContext RdrName -> RdrNameMatch -> RnM (RenamedMatch, FreeVars)
+rnMatch :: HsMatchContext Name -> RdrNameMatch -> RnM (RenamedMatch, FreeVars)
rnMatch ctxt match@(Match pats maybe_rhs_sig grhss)
= addSrcLoc (getMatchLoc match) $
- -- Bind pattern-bound type variables
- let
- rhs_sig_tys = case maybe_rhs_sig of
- Nothing -> []
- Just ty -> [ty]
- pat_sig_tys = collectSigTysFromPats pats
- doc_sig = text "In a result type-signature"
- doc_pat = pprMatchContext ctxt
- in
- bindPatSigTyVars (rhs_sig_tys ++ pat_sig_tys) $
-
- -- Note that we do a single bindLocalsRn for all the
- -- matches together, so that we spot the repeated variable in
- -- f x x = 1
- bindLocalsFVRn doc_pat (collectPatsBinders pats) $ \ new_binders ->
-
- mapFvRn rnPat pats `thenM` \ (pats', pat_fvs) ->
- rnGRHSs grhss `thenM` \ (grhss', grhss_fvs) ->
+ -- Deal with the rhs type signature
+ bindPatSigTyVarsFV rhs_sig_tys $
doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
(case maybe_rhs_sig of
Nothing -> returnM (Nothing, emptyFVs)
returnM (Nothing, emptyFVs)
) `thenM` \ (maybe_rhs_sig', ty_fvs) ->
- let
- binder_set = mkNameSet new_binders
- unused_binders = nameSetToList (binder_set `minusNameSet` grhss_fvs)
- all_fvs = grhss_fvs `plusFV` pat_fvs `plusFV` ty_fvs
- in
- warnUnusedMatches unused_binders `thenM_`
-
- returnM (Match pats' maybe_rhs_sig' grhss', all_fvs)
- -- The bindLocals and bindTyVars will remove the bound FVs
+ -- Now the main event
+ rnPatsAndThen ctxt pats $ \ pats' ->
+ rnGRHSs ctxt grhss `thenM` \ (grhss', grhss_fvs) ->
+
+ returnM (Match pats' maybe_rhs_sig' grhss', grhss_fvs `plusFV` ty_fvs)
+ -- The bindPatSigTyVarsFV and rnPatsAndThen will remove the bound FVs
+ where
+ rhs_sig_tys = case maybe_rhs_sig of
+ Nothing -> []
+ Just ty -> [ty]
+ doc_sig = text "In a result type-signature"
\end{code}
%************************************************************************
\begin{code}
-rnGRHSs :: RdrNameGRHSs -> RnM (RenamedGRHSs, FreeVars)
+rnGRHSs :: HsMatchContext Name -> RdrNameGRHSs -> RnM (RenamedGRHSs, FreeVars)
-rnGRHSs (GRHSs grhss binds _)
- = rnBinds binds $ \ binds' ->
- mapFvRn rnGRHS grhss `thenM` \ (grhss', fvGRHSs) ->
+rnGRHSs ctxt (GRHSs grhss binds _)
+ = rnBindsAndThen binds $ \ binds' ->
+ mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) ->
returnM (GRHSs grhss' binds' placeHolderType, fvGRHSs)
-rnGRHS (GRHS guarded locn)
- = doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
- addSrcLoc locn $
- (if not (opt_GlasgowExts || is_standard_guard guarded) then
- addWarn (nonStdGuardErr guarded)
- else
- returnM ()
- ) `thenM_`
-
- rnStmts guarded `thenM` \ ((_, guarded'), fvs) ->
+rnGRHS ctxt (GRHS guarded locn)
+ = addSrcLoc locn $
+ doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
+ checkM (opt_GlasgowExts || is_standard_guard guarded)
+ (addWarn (nonStdGuardErr guarded)) `thenM_`
+
+ rnStmts (PatGuard ctxt) guarded `thenM` \ (guarded', fvs) ->
returnM (GRHS guarded' locn, fvs)
where
-- Standard Haskell 1.4 guards are just a single boolean
= lookupOccRn v `thenM` \ name ->
if name `hasKey` assertIdKey && not opt_IgnoreAsserts then
-- We expand it to (GHC.Err.assertError location_string)
- mkAssertErrorExpr
+ mkAssertErrorExpr `thenM` \ (e, fvs) ->
+ returnM (e, fvs `addOneFV` name)
+ -- Keep 'assert' as a free var, to ensure it's not reported as unused!
else
-- The normal case. Even if the Id was 'assert', if we are
-- ignoring assertions we leave it as GHC.Base.assert;
returnM (HsPar e', fvs_e)
-- Template Haskell extensions
-rnExpr (HsBracket br_body)
- = checkGHCI (thErr "bracket") `thenM_`
- rnBracket br_body `thenM` \ (body', fvs_e) ->
- returnM (HsBracket body', fvs_e `addOneFV` qTyConName)
- -- We use the Q tycon as a proxy to haul in all the smart
- -- constructors; see the hack in RnIfaces
-
-rnExpr (HsSplice n e)
- = checkGHCI (thErr "splice") `thenM_`
- getSrcLocM `thenM` \ loc ->
- newLocalsRn [(n,loc)] `thenM` \ [n'] ->
- rnExpr e `thenM` \ (e', fvs_e) ->
- returnM (HsSplice n' e', fvs_e)
+-- Don't ifdef-GHCI them because we want to fail gracefully
+-- (not with an rnExpr crash) in a stage-1 compiler.
+rnExpr e@(HsBracket br_body loc)
+ = addSrcLoc loc $
+ checkTH e "bracket" `thenM_`
+ rnBracket br_body `thenM` \ (body', fvs_e) ->
+ returnM (HsBracket body' loc, fvs_e `plusFV` thProxyName)
+
+rnExpr e@(HsSplice n splice loc)
+ = addSrcLoc loc $
+ checkTH e "splice" `thenM_`
+ newLocalsRn [(n,loc)] `thenM` \ [n'] ->
+ rnExpr splice `thenM` \ (splice', fvs_e) ->
+ returnM (HsSplice n' splice' loc, fvs_e `plusFV` thProxyName)
+
+rnExpr e@(HsReify (Reify flavour name))
+ = checkTH e "reify" `thenM_`
+ lookupGlobalOccRn name `thenM` \ name' ->
+ -- For now, we can only reify top-level things
+ returnM (HsReify (Reify flavour name'), unitFV name' `plusFV` thProxyName)
rnExpr section@(SectionL expr op)
= rnExpr expr `thenM` \ (expr', fvs_expr) ->
cReturnableClassName,
ioDataConName])
+rnExpr (HsCoreAnn ann expr)
+ = rnExpr expr `thenM` \ (expr', fvs_expr) ->
+ returnM (HsCoreAnn ann expr', fvs_expr)
+
rnExpr (HsSCC lbl expr)
= rnExpr expr `thenM` \ (expr', fvs_expr) ->
returnM (HsSCC lbl expr', fvs_expr)
returnM (HsCase new_expr new_ms src_loc, e_fvs `plusFV` ms_fvs)
rnExpr (HsLet binds expr)
- = rnBinds binds $ \ binds' ->
+ = rnBindsAndThen binds $ \ binds' ->
rnExpr expr `thenM` \ (expr',fvExpr) ->
returnM (HsLet binds' expr', fvExpr)
-rnExpr (HsWith expr binds is_with)
- = warnIf is_with withWarning `thenM_`
- rnExpr expr `thenM` \ (expr',fvExpr) ->
- rnIPBinds binds `thenM` \ (binds',fvBinds) ->
- returnM (HsWith expr' binds' is_with, fvExpr `plusFV` fvBinds)
-
-rnExpr e@(HsDo do_or_lc stmts _ ty src_loc)
+rnExpr e@(HsDo do_or_lc stmts _ _ src_loc)
= addSrcLoc src_loc $
- rnStmts stmts `thenM` \ ((_, stmts'), fvs) ->
+ rnStmts do_or_lc stmts `thenM` \ (stmts', fvs) ->
-- Check the statement list ends in an expression
case last stmts' of {
ResultStmt _ _ -> returnM () ;
- _ -> addErr (doStmtListErr e)
+ _ -> addErr (doStmtListErr do_or_lc e)
} `thenM_`
-- Generate the rebindable syntax for the monad
- (case do_or_lc of
- DoExpr -> mapAndUnzipM lookupSyntaxName monadNames
- other -> returnM ([], [])
- ) `thenM` \ (monad_names', monad_fvs) ->
+ lookupSyntaxNames syntax_names `thenM` \ (syntax_names', monad_fvs) ->
- returnM (HsDo do_or_lc stmts' monad_names' placeHolderType src_loc,
- fvs `plusFV` implicit_fvs `plusFV` plusFVs monad_fvs)
+ returnM (HsDo do_or_lc stmts' syntax_names' placeHolderType src_loc,
+ fvs `plusFV` implicit_fvs do_or_lc `plusFV` monad_fvs)
where
- implicit_fvs = case do_or_lc of
- PArrComp -> mkFVs [replicatePName, mapPName, filterPName,
- crossPName, zipPName]
- ListComp -> mkFVs [foldrName, buildName]
- DoExpr -> emptyFVs
+ implicit_fvs PArrComp = mkFVs [replicatePName, mapPName, filterPName, crossPName, zipPName]
+ implicit_fvs ListComp = mkFVs [foldrName, buildName]
+ implicit_fvs DoExpr = emptyFVs
+ implicit_fvs MDoExpr = emptyFVs
+
+ syntax_names = case do_or_lc of
+ DoExpr -> monadNames
+ MDoExpr -> monadNames ++ [mfixName]
+ other -> []
rnExpr (ExplicitList _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
returnM (ExplicitPArr placeHolderType exps',
fvs `addOneFV` toPName `addOneFV` parrTyCon_name)
-rnExpr (ExplicitTuple exps boxity)
- = rnExprs exps `thenM` \ (exps', fvs) ->
+rnExpr e@(ExplicitTuple exps boxity)
+ = checkTupSize tup_size `thenM_`
+ rnExprs exps `thenM` \ (exps', fvs) ->
returnM (ExplicitTuple exps' boxity, fvs `addOneFV` tycon_name)
where
- tycon_name = tupleTyCon_name boxity (length exps)
+ tup_size = length exps
+ tycon_name = tupleTyCon_name boxity tup_size
rnExpr (RecordCon con_id rbinds)
= lookupOccRn con_id `thenM` \ conname ->
doc = text "In a type argument"
rnExpr (ArithSeqIn seq)
- = rn_seq seq `thenM` \ (new_seq, fvs) ->
+ = rnArithSeq seq `thenM` \ (new_seq, fvs) ->
returnM (ArithSeqIn new_seq, fvs `addOneFV` enumClassName)
- where
- rn_seq (From expr)
- = rnExpr expr `thenM` \ (expr', fvExpr) ->
- returnM (From expr', fvExpr)
-
- rn_seq (FromThen expr1 expr2)
- = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
-
- rn_seq (FromTo expr1 expr2)
- = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
-
- rn_seq (FromThenTo expr1 expr2 expr3)
- = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- rnExpr expr3 `thenM` \ (expr3', fvExpr3) ->
- returnM (FromThenTo expr1' expr2' expr3',
- plusFVs [fvExpr1, fvExpr2, fvExpr3])
rnExpr (PArrSeqIn seq)
- = rn_seq seq `thenM` \ (new_seq, fvs) ->
+ = rnArithSeq seq `thenM` \ (new_seq, fvs) ->
returnM (PArrSeqIn new_seq,
- fvs `plusFV` mkFVs [enumFromToPName, enumFromThenToPName])
- where
-
- -- the parser shouldn't generate these two
- --
- rn_seq (From _ ) = panic "RnExpr.rnExpr: Infinite parallel array!"
- rn_seq (FromThen _ _) = panic "RnExpr.rnExpr: Infinite parallel array!"
-
- rn_seq (FromTo expr1 expr2)
- = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
- rn_seq (FromThenTo expr1 expr2 expr3)
- = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- rnExpr expr3 `thenM` \ (expr3', fvExpr3) ->
- returnM (FromThenTo expr1' expr2' expr3',
- plusFVs [fvExpr1, fvExpr2, fvExpr3])
+ fvs `plusFV` mkFVs [enumFromToPName, enumFromThenToPName])
\end{code}
These three are pattern syntax appearing in expressions.
returnM (EWildPat, emptyFVs)
\end{code}
+%************************************************************************
+%* *
+ Arrow notation
+%* *
+%************************************************************************
+
+\begin{code}
+rnExpr (HsProc pat body src_loc)
+ = addSrcLoc src_loc $
+ rnPatsAndThen ProcExpr [pat] $ \ [pat'] ->
+ rnCmdTop body `thenM` \ (body',fvBody) ->
+ returnM (HsProc pat' body' src_loc, fvBody)
+
+rnExpr (HsArrApp arrow arg _ ho rtl srcloc)
+ = rnExpr arrow `thenM` \ (arrow',fvArrow) ->
+ rnExpr arg `thenM` \ (arg',fvArg) ->
+ returnM (HsArrApp arrow' arg' placeHolderType ho rtl srcloc,
+ fvArrow `plusFV` fvArg)
+
+-- infix form
+rnExpr (HsArrForm op (Just _) [arg1, arg2] srcloc)
+ = rnExpr op `thenM` \ (op'@(HsVar op_name),fv_op) ->
+ rnCmdTop arg1 `thenM` \ (arg1',fv_arg1) ->
+ rnCmdTop arg2 `thenM` \ (arg2',fv_arg2) ->
+
+ -- Deal with fixity
+
+ lookupFixityRn op_name `thenM` \ fixity ->
+ mkOpFormRn arg1' op' fixity arg2' `thenM` \ final_e ->
+
+ returnM (final_e,
+ fv_arg1 `plusFV` fv_op `plusFV` fv_arg2)
+
+rnExpr (HsArrForm op fixity cmds srcloc)
+ = rnExpr op `thenM` \ (op',fvOp) ->
+ rnCmdArgs cmds `thenM` \ (cmds',fvCmds) ->
+ returnM (HsArrForm op' fixity cmds' srcloc,
+ fvOp `plusFV` fvCmds)
+
+---------------------------
+-- Deal with fixity (cf mkOpAppRn for the method)
+
+mkOpFormRn :: RenamedHsCmdTop -- Left operand; already rearranged
+ -> RenamedHsExpr -> Fixity -- Operator and fixity
+ -> RenamedHsCmdTop -- Right operand (not an infix)
+ -> RnM RenamedHsCmd
+
+---------------------------
+-- (e11 `op1` e12) `op2` e2
+mkOpFormRn a1@(HsCmdTop (HsArrForm op1 (Just fix1) [a11,a12] loc1) _ _ _) op2 fix2 a2
+ | nofix_error
+ = addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
+ returnM (HsArrForm op2 (Just fix2) [a1, a2] loc1)
+
+ | associate_right
+ = mkOpFormRn a12 op2 fix2 a2 `thenM` \ new_c ->
+ returnM (HsArrForm op1 (Just fix1)
+ [a11, HsCmdTop new_c [] placeHolderType []] loc1)
+ where
+ (nofix_error, associate_right) = compareFixity fix1 fix2
+
+---------------------------
+-- Default case
+mkOpFormRn arg1 op fix arg2 -- Default case, no rearrangment
+ = returnM (HsArrForm op (Just fix) [arg1, arg2] noSrcLoc)
+
+\end{code}
%************************************************************************
%* *
-\subsubsection{@Rbinds@s and @Rpats@s: in record expressions}
+ Arrow commands
%* *
%************************************************************************
\begin{code}
-rnRbinds str rbinds
- = mappM_ field_dup_err dup_fields `thenM_`
- mapFvRn rn_rbind rbinds `thenM` \ (rbinds', fvRbind) ->
- returnM (rbinds', fvRbind)
- where
- (_, dup_fields) = removeDups compare [ f | (f,_) <- rbinds ]
+rnCmdArgs [] = returnM ([], emptyFVs)
+rnCmdArgs (arg:args)
+ = rnCmdTop arg `thenM` \ (arg',fvArg) ->
+ rnCmdArgs args `thenM` \ (args',fvArgs) ->
+ returnM (arg':args', fvArg `plusFV` fvArgs)
+
+rnCmdTop (HsCmdTop cmd _ _ _)
+ = rnExpr (convertOpFormsCmd cmd) `thenM` \ (cmd', fvCmd) ->
+ let
+ cmd_names = [arrAName, composeAName, firstAName] ++
+ nameSetToList (methodNamesCmd cmd')
+ in
+ -- Generate the rebindable syntax for the monad
+ lookupSyntaxNames cmd_names `thenM` \ (cmd_names', cmd_fvs) ->
- field_dup_err dups = addErr (dupFieldErr str dups)
+ returnM (HsCmdTop cmd' [] placeHolderType cmd_names',
+ fvCmd `plusFV` cmd_fvs)
- rn_rbind (field, expr)
- = lookupGlobalOccRn field `thenM` \ fieldname ->
- rnExpr expr `thenM` \ (expr', fvExpr) ->
- returnM ((fieldname, expr'), fvExpr `addOneFV` fieldname)
+---------------------------------------------------
+-- convert OpApp's in a command context to HsArrForm's
-rnRpats rpats
- = mappM_ field_dup_err dup_fields `thenM_`
- mapFvRn rn_rpat rpats `thenM` \ (rpats', fvs) ->
- returnM (rpats', fvs)
- where
- (_, dup_fields) = removeDups compare [ f | (f,_) <- rpats ]
+convertOpFormsCmd :: HsCmd id -> HsCmd id
- field_dup_err dups = addErr (dupFieldErr "pattern" dups)
+convertOpFormsCmd (HsApp c e) = HsApp (convertOpFormsCmd c) e
- rn_rpat (field, pat)
- = lookupGlobalOccRn field `thenM` \ fieldname ->
- rnPat pat `thenM` \ (pat', fvs) ->
- returnM ((fieldname, pat'), fvs `addOneFV` fieldname)
+convertOpFormsCmd (HsLam match) = HsLam (convertOpFormsMatch match)
+
+convertOpFormsCmd (OpApp c1 op fixity c2)
+ = let
+ arg1 = HsCmdTop (convertOpFormsCmd c1) [] placeHolderType []
+ arg2 = HsCmdTop (convertOpFormsCmd c2) [] placeHolderType []
+ in
+ HsArrForm op (Just fixity) [arg1, arg2] noSrcLoc
+
+convertOpFormsCmd (HsPar c) = HsPar (convertOpFormsCmd c)
+
+convertOpFormsCmd (HsCase exp matches locn)
+ = HsCase exp (map convertOpFormsMatch matches) locn
+
+convertOpFormsCmd (HsIf exp c1 c2 locn)
+ = HsIf exp (convertOpFormsCmd c1) (convertOpFormsCmd c2) locn
+
+convertOpFormsCmd (HsLet binds cmd)
+ = HsLet binds (convertOpFormsCmd cmd)
+
+convertOpFormsCmd (HsDo ctxt stmts ids ty locn)
+ = HsDo ctxt (map convertOpFormsStmt stmts) ids ty locn
+
+-- Anything else is unchanged. This includes HsArrForm (already done),
+-- things with no sub-commands, and illegal commands (which will be
+-- caught by the type checker)
+convertOpFormsCmd c = c
+
+convertOpFormsStmt (BindStmt pat cmd locn)
+ = BindStmt pat (convertOpFormsCmd cmd) locn
+convertOpFormsStmt (ResultStmt cmd locn)
+ = ResultStmt (convertOpFormsCmd cmd) locn
+convertOpFormsStmt (ExprStmt cmd ty locn)
+ = ExprStmt (convertOpFormsCmd cmd) ty locn
+convertOpFormsStmt (RecStmt stmts lvs rvs es)
+ = RecStmt (map convertOpFormsStmt stmts) lvs rvs es
+convertOpFormsStmt stmt = stmt
+
+convertOpFormsMatch (Match pat mty grhss)
+ = Match pat mty (convertOpFormsGRHSs grhss)
+
+convertOpFormsGRHSs (GRHSs grhss binds ty)
+ = GRHSs (map convertOpFormsGRHS grhss) binds ty
+
+convertOpFormsGRHS (GRHS stmts locn)
+ = let
+ (ResultStmt cmd locn') = last stmts
+ in
+ GRHS (init stmts ++ [ResultStmt (convertOpFormsCmd cmd) locn']) locn
+
+---------------------------------------------------
+type CmdNeeds = FreeVars -- Only inhabitants are
+ -- appAName, choiceAName, loopAName
+
+-- find what methods the Cmd needs (loop, choice, apply)
+methodNamesCmd :: HsCmd Name -> CmdNeeds
+
+methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsFirstOrderApp _rtl _srcloc)
+ = emptyFVs
+methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsHigherOrderApp _rtl _srcloc)
+ = unitFV appAName
+methodNamesCmd cmd@(HsArrForm {}) = emptyFVs
+
+methodNamesCmd (HsPar c) = methodNamesCmd c
+
+methodNamesCmd (HsIf p c1 c2 loc)
+ = methodNamesCmd c1 `plusFV` methodNamesCmd c2 `addOneFV` choiceAName
+
+methodNamesCmd (HsLet b c) = methodNamesCmd c
+
+methodNamesCmd (HsDo sc stmts rbs ty loc) = methodNamesStmts stmts
+
+methodNamesCmd (HsApp c e) = methodNamesCmd c
+
+methodNamesCmd (HsLam match) = methodNamesMatch match
+
+methodNamesCmd (HsCase scrut matches loc)
+ = plusFVs (map methodNamesMatch matches) `addOneFV` choiceAName
+
+methodNamesCmd other = emptyFVs
+ -- Other forms can't occur in commands, but it's not convenient
+ -- to error here so we just do what's convenient.
+ -- The type checker will complain later
+
+---------------------------------------------------
+methodNamesMatch (Match pats sig_ty grhss) = methodNamesGRHSs grhss
+
+-------------------------------------------------
+methodNamesGRHSs (GRHSs grhss binds ty) = plusFVs (map methodNamesGRHS grhss)
+
+-------------------------------------------------
+methodNamesGRHS (GRHS stmts loc) = methodNamesStmt (last stmts)
+
+---------------------------------------------------
+methodNamesStmts stmts = plusFVs (map methodNamesStmt stmts)
+
+---------------------------------------------------
+methodNamesStmt (ResultStmt cmd loc) = methodNamesCmd cmd
+methodNamesStmt (ExprStmt cmd ty loc) = methodNamesCmd cmd
+methodNamesStmt (BindStmt pat cmd loc) = methodNamesCmd cmd
+methodNamesStmt (RecStmt stmts lvs rvs es)
+ = methodNamesStmts stmts `addOneFV` loopAName
+methodNamesStmt (LetStmt b) = emptyFVs
+methodNamesStmt (ParStmt ss) = emptyFVs
+ -- ParStmt can't occur in commands, but it's not convenient to error
+ -- here so we just do what's convenient
\end{code}
+
%************************************************************************
%* *
-\subsubsection{@rnIPBinds@s: in implicit parameter bindings} *
+ Arithmetic sequences
%* *
%************************************************************************
\begin{code}
-rnIPBinds [] = returnM ([], emptyFVs)
-rnIPBinds ((n, expr) : binds)
- = newIPName n `thenM` \ name ->
- rnExpr expr `thenM` \ (expr',fvExpr) ->
- rnIPBinds binds `thenM` \ (binds',fvBinds) ->
- returnM ((name, expr') : binds', fvExpr `plusFV` fvBinds)
+rnArithSeq (From expr)
+ = rnExpr expr `thenM` \ (expr', fvExpr) ->
+ returnM (From expr', fvExpr)
+
+rnArithSeq (FromThen expr1 expr2)
+ = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
+ rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
+ returnM (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
+
+rnArithSeq (FromTo expr1 expr2)
+ = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
+ rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
+ returnM (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
+
+rnArithSeq (FromThenTo expr1 expr2 expr3)
+ = rnExpr expr1 `thenM` \ (expr1', fvExpr1) ->
+ rnExpr expr2 `thenM` \ (expr2', fvExpr2) ->
+ rnExpr expr3 `thenM` \ (expr3', fvExpr3) ->
+ returnM (FromThenTo expr1' expr2' expr3',
+ plusFVs [fvExpr1, fvExpr2, fvExpr3])
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsubsection{@Rbinds@s and @Rpats@s: in record expressions}
+%* *
+%************************************************************************
+\begin{code}
+rnRbinds str rbinds
+ = mappM_ field_dup_err dup_fields `thenM_`
+ mapFvRn rn_rbind rbinds `thenM` \ (rbinds', fvRbind) ->
+ returnM (rbinds', fvRbind)
+ where
+ (_, dup_fields) = removeDups compare [ f | (f,_) <- rbinds ]
+
+ field_dup_err dups = addErr (dupFieldErr str dups)
+
+ rn_rbind (field, expr)
+ = lookupGlobalOccRn field `thenM` \ fieldname ->
+ rnExpr expr `thenM` \ (expr', fvExpr) ->
+ returnM ((fieldname, expr'), fvExpr `addOneFV` fieldname)
\end{code}
%************************************************************************
returnM (TypBr t', fvs)
where
doc = ptext SLIT("In a Template-Haskell quoted type")
-rnBracket (DecBr ds) = rnSrcDecls ds `thenM` \ (tcg_env, ds', fvs) ->
- -- Discard the tcg_env; it contains the extended global RdrEnv
- -- because there is no scope that these decls cover (yet!)
- returnM (DecBr ds', fvs)
+rnBracket (DecBr group)
+ = importsFromLocalDecls group `thenM` \ (rdr_env, avails) ->
+ -- Discard avails (not useful here)
+
+ updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl }) $
+
+ rnSrcDecls group `thenM` \ (tcg_env, group', dus) ->
+ -- Discard the tcg_env; it contains only extra info about fixity
+
+ returnM (DecBr group', duUses dus `minusNameSet` duDefs dus)
\end{code}
%************************************************************************
%* *
%************************************************************************
-Note that although some bound vars may appear in the free var set for
-the first qual, these will eventually be removed by the caller. For
-example, if we have @[p | r <- s, q <- r, p <- q]@, when doing
-@[q <- r, p <- q]@, the free var set for @q <- r@ will
-be @{r}@, and the free var set for the entire Quals will be @{r}@. This
-@r@ will be removed only when we finally return from examining all the
-Quals.
-
\begin{code}
-rnStmts :: [RdrNameStmt]
- -> RnM (([Name], [RenamedStmt]), FreeVars)
-
-rnStmts []
- = returnM (([], []), emptyFVs)
-
-rnStmts (stmt:stmts)
- = getLocalRdrEnv `thenM` \ name_env ->
- rnStmt stmt $ \ stmt' ->
- rnStmts stmts `thenM` \ ((binders, stmts'), fvs) ->
- returnM ((binders, stmt' : stmts'), fvs)
-
-rnStmt :: RdrNameStmt
- -> (RenamedStmt -> RnM (([Name], a), FreeVars))
- -> RnM (([Name], a), FreeVars)
--- The thing list of names returned is the list returned by the
--- thing_inside, plus the binders of the arguments stmt
-
-rnStmt (ParStmt stmtss) thing_inside
- = mapFvRn rnStmts stmtss `thenM` \ (bndrstmtss, fv_stmtss) ->
- let binderss = map fst bndrstmtss
- checkBndrs all_bndrs bndrs
- = checkErr (null (intersectBy eqOcc all_bndrs bndrs)) err `thenM_`
- returnM (bndrs ++ all_bndrs)
- eqOcc n1 n2 = nameOccName n1 == nameOccName n2
- err = text "duplicate binding in parallel list comprehension"
+rnStmts :: HsStmtContext Name -> [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
+
+rnStmts MDoExpr stmts = rnMDoStmts stmts
+rnStmts ctxt stmts = rnNormalStmts ctxt stmts
+
+rnNormalStmts :: HsStmtContext Name -> [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
+-- Used for cases *other* than recursive mdo
+-- Implements nested scopes
+
+rnNormalStmts ctxt [] = returnM ([], emptyFVs)
+ -- Happens at the end of the sub-lists of a ParStmts
+
+rnNormalStmts ctxt (ExprStmt expr _ src_loc : stmts)
+ = addSrcLoc src_loc $
+ rnExpr expr `thenM` \ (expr', fv_expr) ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
+ returnM (ExprStmt expr' placeHolderType src_loc : stmts',
+ fv_expr `plusFV` fvs)
+
+rnNormalStmts ctxt [ResultStmt expr src_loc]
+ = addSrcLoc src_loc $
+ rnExpr expr `thenM` \ (expr', fv_expr) ->
+ returnM ([ResultStmt expr' src_loc], fv_expr)
+
+rnNormalStmts ctxt (BindStmt pat expr src_loc : stmts)
+ = addSrcLoc src_loc $
+ rnExpr expr `thenM` \ (expr', fv_expr) ->
+ -- The binders do not scope over the expression
+
+ rnPatsAndThen (StmtCtxt ctxt) [pat] $ \ [pat'] ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
+ returnM (BindStmt pat' expr' src_loc : stmts',
+ fv_expr `plusFV` fvs) -- fv_expr shouldn't really be filtered by
+ -- the rnPatsAndThen, but it does not matter
+
+rnNormalStmts ctxt (LetStmt binds : stmts)
+ = checkErr (ok ctxt binds) (badIpBinds binds) `thenM_`
+ rnBindsAndThen binds ( \ binds' ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
+ returnM (LetStmt binds' : stmts', fvs))
+ where
+ -- We do not allow implicit-parameter bindings in a parallel
+ -- list comprehension. I'm not sure what it might mean.
+ ok (ParStmtCtxt _) (IPBinds _ _) = False
+ ok _ _ = True
+
+rnNormalStmts ctxt (ParStmt stmtss : stmts)
+ = doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
+ checkM opt_GlasgowExts parStmtErr `thenM_`
+ mapFvRn rn_branch stmtss `thenM` \ (stmtss', fv_stmtss) ->
+ let
+ bndrss :: [[Name]] -- NB: Name, not RdrName
+ bndrss = map collectStmtsBinders stmtss'
+ (bndrs, dups) = removeDups cmpByOcc (concat bndrss)
in
- foldlM checkBndrs [] binderss `thenM` \ new_binders ->
- bindLocalNamesFV new_binders $
- thing_inside (ParStmtOut bndrstmtss)`thenM` \ ((rest_bndrs, result), fv_rest) ->
- returnM ((new_binders ++ rest_bndrs, result), fv_stmtss `plusFV` fv_rest)
+ mappM dupErr dups `thenM` \ _ ->
+ bindLocalNamesFV bndrs $
+ -- Note: binders are returned in scope order, so one may
+ -- shadow the next; e.g. x <- xs; x <- ys
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
-rnStmt (BindStmt pat expr src_loc) thing_inside
- = addSrcLoc src_loc $
- rnExpr expr `thenM` \ (expr', fv_expr) ->
- bindPatSigTyVars (collectSigTysFromPat pat) $
- bindLocalsFVRn doc (collectPatBinders pat) $ \ new_binders ->
- rnPat pat `thenM` \ (pat', fv_pat) ->
- thing_inside (BindStmt pat' expr' src_loc) `thenM` \ ((rest_binders, result), fvs) ->
- returnM ((new_binders ++ rest_binders, result),
- fv_expr `plusFV` fvs `plusFV` fv_pat)
+ -- Cut down the exported binders to just the ones neede in the body
+ let
+ used_bndrs_s = map (filter (`elemNameSet` fvs)) bndrss
+ in
+ returnM (ParStmt (stmtss' `zip` used_bndrs_s) : stmts',
+ fv_stmtss `plusFV` fvs)
+
where
- doc = text "In a pattern in 'do' binding"
+ rn_branch (stmts, _) = rnNormalStmts (ParStmtCtxt ctxt) stmts
-rnStmt (ExprStmt expr _ src_loc) thing_inside
- = addSrcLoc src_loc $
- rnExpr expr `thenM` \ (expr', fv_expr) ->
- thing_inside (ExprStmt expr' placeHolderType src_loc) `thenM` \ (result, fvs) ->
- returnM (result, fv_expr `plusFV` fvs)
+ cmpByOcc n1 n2 = nameOccName n1 `compare` nameOccName n2
+ dupErr (v:_) = addErr (ptext SLIT("Duplicate binding in parallel list comprehension for:")
+ <+> quotes (ppr v))
-rnStmt (ResultStmt expr src_loc) thing_inside
- = addSrcLoc src_loc $
- rnExpr expr `thenM` \ (expr', fv_expr) ->
- thing_inside (ResultStmt expr' src_loc) `thenM` \ (result, fvs) ->
- returnM (result, fv_expr `plusFV` fvs)
-
-rnStmt (LetStmt binds) thing_inside
- = rnBinds binds $ \ binds' ->
- let new_binders = collectHsBinders binds' in
- thing_inside (LetStmt binds') `thenM` \ ((rest_binders, result), fvs) ->
- returnM ((new_binders ++ rest_binders, result), fvs )
+rnNormalStmts ctxt (RecStmt rec_stmts _ _ _ : stmts)
+ = bindLocalsRn doc (collectStmtsBinders rec_stmts) $ \ _ ->
+ rn_rec_stmts rec_stmts `thenM` \ segs ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
+ let
+ segs_w_fwd_refs = addFwdRefs segs
+ (ds, us, fs, rec_stmts') = unzip4 segs_w_fwd_refs
+ later_vars = nameSetToList (plusFVs ds `intersectNameSet` fvs)
+ fwd_vars = nameSetToList (plusFVs fs)
+ uses = plusFVs us
+ in
+ returnM (RecStmt rec_stmts' later_vars fwd_vars [] : stmts', uses `plusFV` fvs)
+ where
+ doc = text "In a recursive do statement"
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsubsection{mdo expressions}
+%* *
+%************************************************************************
+
+\begin{code}
+type FwdRefs = NameSet
+type Segment stmts = (Defs,
+ Uses, -- May include defs
+ FwdRefs, -- A subset of uses that are
+ -- (a) used before they are bound in this segment, or
+ -- (b) used here, and bound in subsequent segments
+ stmts) -- Either Stmt or [Stmt]
+
+
+----------------------------------------------------
+rnMDoStmts :: [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
+rnMDoStmts stmts
+ = -- Step1: bring all the binders of the mdo into scope
+ -- Remember that this also removes the binders from the
+ -- finally-returned free-vars
+ bindLocalsRn doc (collectStmtsBinders stmts) $ \ _ ->
+
+ -- Step 2: Rename each individual stmt, making a
+ -- singleton segment. At this stage the FwdRefs field
+ -- isn't finished: it's empty for all except a BindStmt
+ -- for which it's the fwd refs within the bind itself
+ -- (This set may not be empty, because we're in a recursive
+ -- context.)
+ rn_rec_stmts stmts `thenM` \ segs ->
+ let
+ -- Step 3: Fill in the fwd refs.
+ -- The segments are all singletons, but their fwd-ref
+ -- field mentions all the things used by the segment
+ -- that are bound after their use
+ segs_w_fwd_refs = addFwdRefs segs
+
+ -- Step 4: Group together the segments to make bigger segments
+ -- Invariant: in the result, no segment uses a variable
+ -- bound in a later segment
+ grouped_segs = glomSegments segs_w_fwd_refs
+
+ -- Step 5: Turn the segments into Stmts
+ -- Use RecStmt when and only when there are fwd refs
+ -- Also gather up the uses from the end towards the
+ -- start, so we can tell the RecStmt which things are
+ -- used 'after' the RecStmt
+ stmts_w_fvs = segsToStmts grouped_segs
+ in
+ returnM stmts_w_fvs
+ where
+ doc = text "In a mdo-expression"
+
+
+----------------------------------------------------
+rn_rec_stmt :: RdrNameStmt -> RnM [Segment RenamedStmt]
+ -- Rename a Stmt that is inside a RecStmt (or mdo)
+ -- Assumes all binders are already in scope
+ -- Turns each stmt into a singleton Stmt
+
+rn_rec_stmt (ExprStmt expr _ src_loc)
+ = addSrcLoc src_loc (rnExpr expr) `thenM` \ (expr', fvs) ->
+ returnM [(emptyNameSet, fvs, emptyNameSet,
+ ExprStmt expr' placeHolderType src_loc)]
+
+rn_rec_stmt (ResultStmt expr src_loc)
+ = addSrcLoc src_loc (rnExpr expr) `thenM` \ (expr', fvs) ->
+ returnM [(emptyNameSet, fvs, emptyNameSet,
+ ResultStmt expr' src_loc)]
+
+rn_rec_stmt (BindStmt pat expr src_loc)
+ = addSrcLoc src_loc $
+ rnExpr expr `thenM` \ (expr', fv_expr) ->
+ rnPat pat `thenM` \ (pat', fv_pat) ->
+ let
+ bndrs = mkNameSet (collectPatBinders pat')
+ fvs = fv_expr `plusFV` fv_pat
+ in
+ returnM [(bndrs, fvs, bndrs `intersectNameSet` fvs,
+ BindStmt pat' expr' src_loc)]
+
+rn_rec_stmt (LetStmt binds)
+ = rnBinds binds `thenM` \ (binds', du_binds) ->
+ returnM [(duDefs du_binds, duUses du_binds,
+ emptyNameSet, LetStmt binds')]
+
+rn_rec_stmt (RecStmt stmts _ _ _) -- Flatten Rec inside Rec
+ = rn_rec_stmts stmts
+
+rn_rec_stmt stmt@(ParStmt _) -- Syntactically illegal in mdo
+ = pprPanic "rn_rec_stmt" (ppr stmt)
+
+---------------------------------------------
+rn_rec_stmts :: [RdrNameStmt] -> RnM [Segment RenamedStmt]
+rn_rec_stmts stmts = mappM rn_rec_stmt stmts `thenM` \ segs_s ->
+ returnM (concat segs_s)
+
+
+---------------------------------------------
+addFwdRefs :: [Segment a] -> [Segment a]
+-- So far the segments only have forward refs *within* the Stmt
+-- (which happens for bind: x <- ...x...)
+-- This function adds the cross-seg fwd ref info
+
+addFwdRefs pairs
+ = fst (foldr mk_seg ([], emptyNameSet) pairs)
+ where
+ mk_seg (defs, uses, fwds, stmts) (segs, later_defs)
+ = (new_seg : segs, all_defs)
+ where
+ new_seg = (defs, uses, new_fwds, stmts)
+ all_defs = later_defs `unionNameSets` defs
+ new_fwds = fwds `unionNameSets` (uses `intersectNameSet` later_defs)
+ -- Add the downstream fwd refs here
+
+----------------------------------------------------
+-- Glomming the singleton segments of an mdo into
+-- minimal recursive groups.
+--
+-- At first I thought this was just strongly connected components, but
+-- there's an important constraint: the order of the stmts must not change.
+--
+-- Consider
+-- mdo { x <- ...y...
+-- p <- z
+-- y <- ...x...
+-- q <- x
+-- z <- y
+-- r <- x }
+--
+-- Here, the first stmt mention 'y', which is bound in the third.
+-- But that means that the innocent second stmt (p <- z) gets caught
+-- up in the recursion. And that in turn means that the binding for
+-- 'z' has to be included... and so on.
+--
+-- Start at the tail { r <- x }
+-- Now add the next one { z <- y ; r <- x }
+-- Now add one more { q <- x ; z <- y ; r <- x }
+-- Now one more... but this time we have to group a bunch into rec
+-- { rec { y <- ...x... ; q <- x ; z <- y } ; r <- x }
+-- Now one more, which we can add on without a rec
+-- { p <- z ;
+-- rec { y <- ...x... ; q <- x ; z <- y } ;
+-- r <- x }
+-- Finally we add the last one; since it mentions y we have to
+-- glom it togeher with the first two groups
+-- { rec { x <- ...y...; p <- z ; y <- ...x... ;
+-- q <- x ; z <- y } ;
+-- r <- x }
+
+glomSegments :: [Segment RenamedStmt] -> [Segment [RenamedStmt]]
+
+glomSegments [] = []
+glomSegments ((defs,uses,fwds,stmt) : segs)
+ -- Actually stmts will always be a singleton
+ = (seg_defs, seg_uses, seg_fwds, seg_stmts) : others
+ where
+ segs' = glomSegments segs
+ (extras, others) = grab uses segs'
+ (ds, us, fs, ss) = unzip4 extras
+
+ seg_defs = plusFVs ds `plusFV` defs
+ seg_uses = plusFVs us `plusFV` uses
+ seg_fwds = plusFVs fs `plusFV` fwds
+ seg_stmts = stmt : concat ss
+
+ grab :: NameSet -- The client
+ -> [Segment a]
+ -> ([Segment a], -- Needed by the 'client'
+ [Segment a]) -- Not needed by the client
+ -- The result is simply a split of the input
+ grab uses dus
+ = (reverse yeses, reverse noes)
+ where
+ (noes, yeses) = span not_needed (reverse dus)
+ not_needed (defs,_,_,_) = not (intersectsNameSet defs uses)
+
+
+----------------------------------------------------
+segsToStmts :: [Segment [RenamedStmt]] -> ([RenamedStmt], FreeVars)
+
+segsToStmts [] = ([], emptyFVs)
+segsToStmts ((defs, uses, fwds, ss) : segs)
+ = (new_stmt : later_stmts, later_uses `plusFV` uses)
+ where
+ (later_stmts, later_uses) = segsToStmts segs
+ new_stmt | non_rec = head ss
+ | otherwise = RecStmt ss (nameSetToList used_later) (nameSetToList fwds) []
+ where
+ non_rec = isSingleton ss && isEmptyNameSet fwds
+ used_later = defs `intersectNameSet` later_uses
+ -- The ones needed after the RecStmt
\end{code}
%************************************************************************
\end{code}
\begin{code}
-mkConOpPatRn :: Name -> Fixity -> RenamedPat -> RenamedPat
- -> RnM RenamedPat
-
-mkConOpPatRn op2 fix2 p1@(ConPatIn op1 (InfixCon p11 p12)) p2
- = lookupFixityRn op1 `thenM` \ fix1 ->
- let
- (nofix_error, associate_right) = compareFixity fix1 fix2
- in
- if nofix_error then
- addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
- returnM (ConPatIn op2 (InfixCon p1 p2))
- else
- if associate_right then
- mkConOpPatRn op2 fix2 p12 p2 `thenM` \ new_p ->
- returnM (ConPatIn op1 (InfixCon p11 new_p))
- else
- returnM (ConPatIn op2 (InfixCon p1 p2))
-
-mkConOpPatRn op fix p1 p2 -- Default case, no rearrangment
- = ASSERT( not_op_pat p2 )
- returnM (ConPatIn op (InfixCon p1 p2))
-
-not_op_pat (ConPatIn _ (InfixCon _ _)) = False
-not_op_pat other = True
-\end{code}
-
-\begin{code}
checkPrecMatch :: Bool -> Name -> RenamedMatch -> RnM ()
checkPrecMatch False fn match
%************************************************************************
%* *
-\subsubsection{Literals}
-%* *
-%************************************************************************
-
-When literals occur we have to make sure
-that the types and classes they involve
-are made available.
-
-\begin{code}
-litFVs (HsChar c)
- = checkErr (inCharRange c) (bogusCharError c) `thenM_`
- returnM (unitFV charTyCon_name)
-
-litFVs (HsCharPrim c) = returnM (unitFV (getName charPrimTyCon))
-litFVs (HsString s) = returnM (mkFVs [listTyCon_name, charTyCon_name])
-litFVs (HsStringPrim s) = returnM (unitFV (getName addrPrimTyCon))
-litFVs (HsInt i) = returnM (unitFV (getName intTyCon))
-litFVs (HsIntPrim i) = returnM (unitFV (getName intPrimTyCon))
-litFVs (HsFloatPrim f) = returnM (unitFV (getName floatPrimTyCon))
-litFVs (HsDoublePrim d) = returnM (unitFV (getName doublePrimTyCon))
-litFVs (HsLitLit l bogus_ty) = returnM (unitFV cCallableClassName)
-litFVs lit = pprPanic "RnExpr.litFVs" (ppr lit) -- HsInteger and HsRat only appear
- -- in post-typechecker translations
-
-rnOverLit (HsIntegral i _)
- = lookupSyntaxName fromIntegerName `thenM` \ (from_integer_name, fvs) ->
- if inIntRange i then
- returnM (HsIntegral i from_integer_name, fvs)
- else let
- extra_fvs = mkFVs [plusIntegerName, timesIntegerName]
- -- Big integer literals are built, using + and *,
- -- out of small integers (DsUtils.mkIntegerLit)
- -- [NB: plusInteger, timesInteger aren't rebindable...
- -- they are used to construct the argument to fromInteger,
- -- which is the rebindable one.]
- in
- returnM (HsIntegral i from_integer_name, fvs `plusFV` extra_fvs)
-
-rnOverLit (HsFractional i _)
- = lookupSyntaxName fromRationalName `thenM` \ (from_rat_name, fvs) ->
- let
- extra_fvs = mkFVs [ratioDataConName, plusIntegerName, timesIntegerName]
- -- We have to make sure that the Ratio type is imported with
- -- its constructor, because literals of type Ratio t are
- -- built with that constructor.
- -- The Rational type is needed too, but that will come in
- -- as part of the type for fromRational.
- -- The plus/times integer operations may be needed to construct the numerator
- -- and denominator (see DsUtils.mkIntegerLit)
- in
- returnM (HsFractional i from_rat_name, fvs `plusFV` extra_fvs)
-\end{code}
-
-%************************************************************************
-%* *
\subsubsection{Assertion utils}
%* *
%************************************************************************
ppr_op op = quotes (ppr op) -- Here, op can be a Name or a (Var n), where n is a Name
pp_prefix_minus = ptext SLIT("prefix `-'")
-dupFieldErr str (dup:rest)
- = hsep [ptext SLIT("duplicate field name"),
- quotes (ppr dup),
- ptext SLIT("in record"), text str]
-
nonStdGuardErr guard
= hang (ptext
SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)")
) 4 (ppr guard)
-patSigErr ty
- = (ptext SLIT("Illegal signature in pattern:") <+> ppr ty)
- $$ nest 4 (ptext SLIT("Use -fglasgow-exts to permit it"))
-
patSynErr e
= sep [ptext SLIT("Pattern syntax in expression context:"),
nest 4 (ppr e)]
-thErr what
- = ptext SLIT("Template Haskell") <+> text what <+>
- ptext SLIT("illegal in a stage-1 compiler")
-
-doStmtListErr e
- = sep [ptext SLIT("`do' statements must end in expression:"),
+doStmtListErr do_or_lc e
+ = sep [quotes (text binder_name) <+> ptext SLIT("statements must end in expression:"),
nest 4 (ppr e)]
-
-bogusCharError c
- = ptext SLIT("character literal out of range: '\\") <> int c <> char '\''
-
-withWarning
- = sep [quotes (ptext SLIT("with")),
- ptext SLIT("is deprecated, use"),
- quotes (ptext SLIT("let")),
- ptext SLIT("instead")]
+ where
+ binder_name = case do_or_lc of
+ MDoExpr -> "mdo"
+ other -> "do"
+
+#ifdef GHCI
+checkTH e what = returnM () -- OK
+#else
+checkTH e what -- Raise an error in a stage-1 compiler
+ = addErr (vcat [ptext SLIT("Template Haskell") <+> text what <+>
+ ptext SLIT("illegal in a stage-1 compiler"),
+ nest 2 (ppr e)])
+#endif
+
+parStmtErr = addErr (ptext SLIT("Illegal parallel list comprehension: use -fglagow-exts"))
+
+badIpBinds binds
+ = hang (ptext SLIT("Implicit-parameter bindings illegal in a parallel list comprehension:")) 4
+ (ppr binds)
\end{code}