Typecheck arrow notation
\begin{code}
-{-# OPTIONS -w #-}
--- 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 TcArrows ( tcProc ) where
import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho )
import TysWiredIn
import VarSet
import TysPrim
-import Type
import SrcLoc
import Outputable
do { ((exp_ty1, res_ty), coi) <- boxySplitAppTy exp_ty
; ((arr_ty, arg_ty), coi1) <- boxySplitAppTy exp_ty1
; let cmd_env = CmdEnv { cmd_arr = arr_ty }
- ; (pat', cmd') <- tcProcPat pat arg_ty res_ty $
+ ; (pat', cmd') <- tcPat ProcExpr pat arg_ty res_ty $
tcCmdTop cmd_env cmd []
; let res_coi = mkTransCoI coi (mkAppTyCoI exp_ty1 coi1 res_ty IdCo)
; return (pat', cmd', res_coi)
{ expr' <- tc_cmd env expr res_ty
; return (L loc expr') }
+tc_cmd :: CmdEnv -> HsExpr Name -> (CmdStack, TcTauType) -> TcM (HsExpr TcId)
tc_cmd env (HsPar cmd) res_ty
= do { cmd' <- tcCmd env cmd res_ty
; return (HsPar cmd') }
tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
= addErrCtxt (cmdCtxt in_cmd) $ do
- (scrut', scrut_ty) <- addErrCtxt (caseScrutCtxt scrut) $
- tcInferRho scrut
+ (scrut', scrut_ty) <- tcInferRho scrut
matches' <- tcMatchesCase match_ctxt scrut_ty matches res_ty
return (HsCase scrut' matches')
where
-------------------------------------------
-- Lambda
-tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig grhss))] _))
+tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats _maybe_rhs_sig grhss))] _))
(cmd_stk, res_ty)
- = addErrCtxt (matchCtxt match_ctxt match) $
+ = addErrCtxt (pprMatchInCtxt match_ctxt match) $
do { -- Check the cmd stack is big enough
; checkTc (lengthAtLeast cmd_stk n_pats)
(kappaUnderflow cmd)
-- Check the patterns, and the GRHSs inside
- ; (pats', grhss') <- setSrcSpan mtch_loc $
- tcLamPats pats cmd_stk res_ty $
+ ; (pats', grhss') <- setSrcSpan mtch_loc $
+ tcPats LambdaExpr pats cmd_stk res_ty $
tc_grhss grhss
; let match' = L mtch_loc (Match pats' Nothing grhss')
-------------------------------------------
-- Do notation
-tc_cmd env cmd@(HsDo do_or_lc stmts body ty) (cmd_stk, res_ty)
+tc_cmd env cmd@(HsDo do_or_lc stmts body _ty) (cmd_stk, res_ty)
= do { checkTc (null cmd_stk) (nonEmptyCmdStkErr cmd)
; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts res_ty $
tcGuardedCmd env body []
tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
= addErrCtxt (cmdCtxt cmd) $
do { cmds_w_tys <- zipWithM new_cmd_ty cmd_args [1..]
- ; span <- getSrcSpanM
; [w_tv] <- tcInstSkolTyVars ArrowSkol [alphaTyVar]
; let w_ty = mkTyVarTy w_tv -- Just a convenient starting point
(w,ss) = unscramble t
in (w, s:ss)
- other -> (ty, [])
+ _ -> (ty, [])
-----------------------------------------------------------------
-- Base case for illegal commands
-- This is where expressions that aren't commands get rejected
-tc_cmd env cmd _
+tc_cmd _ cmd _
= failWithTc (vcat [ptext (sLit "The expression"), nest 2 (ppr cmd),
ptext (sLit "was found where an arrow command was expected")])
\end{code}
\begin{code}
+mkPairTy :: Type -> Type -> Type
mkPairTy t1 t2 = mkTyConApp pairTyCon [t1,t2]
arrowTyConKind :: Kind -- *->*->*
%************************************************************************
\begin{code}
+cmdCtxt :: HsExpr Name -> SDoc
cmdCtxt cmd = ptext (sLit "In the command:") <+> ppr cmd
-caseScrutCtxt cmd
- = hang (ptext (sLit "In the scrutinee of a case command:")) 4 (ppr cmd)
-
+nonEmptyCmdStkErr :: HsExpr Name -> SDoc
nonEmptyCmdStkErr cmd
= hang (ptext (sLit "Non-empty command stack at command:"))
4 (ppr cmd)
+kappaUnderflow :: HsExpr Name -> SDoc
kappaUnderflow cmd
= hang (ptext (sLit "Command stack underflow at command:"))
4 (ppr cmd)
+badFormFun :: Int -> TcType -> SDoc
badFormFun i tup_ty'
= hang (ptext (sLit "The type of the") <+> speakNth i <+> ptext (sLit "argument of a command form has the wrong shape"))
4 (ptext (sLit "Argument type:") <+> ppr tup_ty')