[project @ 1999-05-26 16:54:22 by simonpj]
[ghc-hetmet.git] / ghc / compiler / typecheck / TcGenDeriv.lhs
index 2819e6a..b043f7d 100644 (file)
@@ -28,19 +28,20 @@ module TcGenDeriv (
 
 import HsSyn           ( InPat(..), HsExpr(..), MonoBinds(..),
                          Match(..), GRHSs(..), Stmt(..), HsLit(..),
-                         HsBinds(..), StmtCtxt(..),
+                         HsBinds(..), StmtCtxt(..), HsType(..),
                          unguardedRHS, mkSimpleMatch
                        )
 import RdrHsSyn                ( mkOpApp, RdrNameMonoBinds, RdrNameHsExpr, RdrNamePat )
 import RdrName         ( RdrName, mkSrcUnqual )
-import BasicTypes      ( RecFlag(..) )
+import RnMonad         ( Fixities )
+import BasicTypes      ( RecFlag(..), Fixity(..), FixityDirection(..) )
 import FieldLabel       ( fieldLabelName )
 import DataCon         ( isNullaryDataCon, dataConTag,
                          dataConRawArgTys, fIRST_TAG,
                          DataCon, ConTag,
                          dataConFieldLabels )
 import Name            ( getOccString, getOccName, getSrcLoc, occNameString, 
-                         nameRdrName, varName,
+                         occNameUserString, nameRdrName, varName,
                          OccName, Name, NamedThing(..), NameSpace
                        )
 
@@ -48,7 +49,7 @@ import PrimOp         ( PrimOp(..) )
 import PrelInfo                -- Lots of RdrNames
 import SrcLoc          ( mkGeneratedSrcLoc, SrcLoc )
 import TyCon           ( TyCon, isNewTyCon, tyConDataCons, isEnumerationTyCon,
-                         maybeTyConSingleCon
+                         maybeTyConSingleCon, tyConFamilySize
                        )
 import Type            ( isUnLiftedType, isUnboxedType, Type )
 import TysPrim         ( charPrimTy, intPrimTy, wordPrimTy, addrPrimTy,
@@ -57,7 +58,8 @@ import TysPrim                ( charPrimTy, intPrimTy, wordPrimTy, addrPrimTy,
 import Util            ( mapAccumL, zipEqual, zipWithEqual,
                          zipWith3Equal, nOfThem )
 import Panic           ( panic, assertPanic )
-import Maybes          ( maybeToBool )
+import Maybes          ( maybeToBool, assocMaybe )
+import Constants
 import List            ( partition, intersperse )
 \end{code}
 
@@ -512,8 +514,8 @@ gen_Enum_binds tycon
                    (mk_easy_App mkInt_RDR [ah_RDR])
                    (mk_easy_App mkInt_RDR [bh_RDR])
                    (HsIf  (HsApp (HsApp (HsVar gt_RDR)
-                                        (HsVar a_RDR))
-                                        (HsVar b_RDR))
+                                        (mk_easy_App mkInt_RDR [ah_RDR]))
+                                        (mk_easy_App mkInt_RDR [bh_RDR]))
                           (HsLit (HsInt 0))
                           (HsVar (maxtag_RDR tycon))
                           tycon_loc))
@@ -758,12 +760,10 @@ gen_Ix_binds tycon
 %*                                                                     *
 %************************************************************************
 
-Ignoring all the infix-ery mumbo jumbo (ToDo)
-
 \begin{code}
-gen_Read_binds :: TyCon -> RdrNameMonoBinds
+gen_Read_binds :: Fixities -> TyCon -> RdrNameMonoBinds
 
-gen_Read_binds tycon
+gen_Read_binds fixities tycon
   = reads_prec `AndMonoBinds` read_list
   where
     tycon_loc = getSrcLoc tycon
@@ -781,50 +781,73 @@ gen_Read_binds tycon
        )
       where
        read_con data_con   -- note: "b" is the string being "read"
-         = let
-               data_con_RDR = qual_orig_name data_con
-               data_con_str= occNameUserString (getOccName data_con)
-               con_arity   = argFieldCount data_con
-               con_expr    = mk_easy_App data_con_RDR as_needed
-               nullary_con = con_arity == 0
-               labels      = dataConFieldLabels data_con
-               lab_fields  = length labels
-
-               as_needed   = take con_arity as_RDRs
-               bs_needed   
-                | lab_fields == 0 = take con_arity bs_RDRs
-                | otherwise       = take (4*lab_fields + 1) bs_RDRs
-                                      -- (label, '=' and field)*n, (n-1)*',' + '{' + '}'
-               con_qual
-                  = BindStmt
-                         (TuplePatIn [LitPatIn (mkHsString data_con_str), 
-                                      d_Pat] True)
-                         (HsApp (HsVar lex_RDR) c_Expr)
-                         tycon_loc
-
-               str_qual str res draw_from
-                  = BindStmt
-                      (TuplePatIn [LitPatIn (mkHsString str), VarPatIn res] True)
-                      (HsApp (HsVar lex_RDR) draw_from)
-                      tycon_loc
+         = HsApp (
+             readParen_Expr read_paren_arg $ HsPar $
+                HsLam (mk_easy_Match tycon_loc [c_Pat] [] $
+                       HsDo ListComp stmts tycon_loc)
+             ) (HsVar b_RDR)
+         where
+          data_con_RDR = qual_orig_name data_con
+          data_con_str = occNameUserString (getOccName data_con)
+          con_arity    = argFieldCount data_con
+          con_expr     = mk_easy_App data_con_RDR as_needed
+          nullary_con  = con_arity == 0
+          labels       = dataConFieldLabels data_con
+          lab_fields   = length labels
+          dc_nm        = getName data_con
+          is_infix     = isInfixOccName data_con_str
+
+          as_needed   = take con_arity as_RDRs
+          bs_needed   
+            | is_infix        = take (1 + con_arity) bs_RDRs
+            | lab_fields == 0 = take con_arity bs_RDRs
+            | otherwise       = take (4*lab_fields + 1) bs_RDRs
+                                 -- (label, '=' and field)*n, (n-1)*',' + '{' + '}'
+
+          (as1:as2:_)     = as_needed
+          (bs1:bs2:bs3:_) = bs_needed
+
+          con_qual 
+            | not is_infix =
+                 BindStmt
+                 (TuplePatIn [LitPatIn (mkHsString data_con_str), d_Pat] True)
+                 (HsApp (HsVar lex_RDR) c_Expr)
+                 tycon_loc
+            | otherwise    =
+                 BindStmt
+                 (TuplePatIn [LitPatIn (mkHsString data_con_str), VarPatIn bs2] True)
+                 (HsApp (HsVar lex_RDR) (HsVar bs1))
+                 tycon_loc
+               
+
+          str_qual str res draw_from =
+               BindStmt
+                 (TuplePatIn [LitPatIn (mkHsString str), VarPatIn res] True)
+                 (HsApp (HsVar lex_RDR) draw_from)
+                 tycon_loc
   
-               read_label f
-                 = let nm = occNameUserString (getOccName (fieldLabelName f))
-                   in 
-                       [str_qual nm, str_qual "="] 
+          read_label f = [str_qual nm, str_qual "="] 
                            -- There might be spaces between the label and '='
-
-               field_quals
-                 | lab_fields == 0 =
-                    snd (mapAccumL mk_qual 
-                                   d_Expr 
-                                   (zipWithEqual "as_needed" 
-                                                 (\ con_field draw_from -> (mk_read_qual con_field,
-                                                                            draw_from))
-                                                 as_needed bs_needed))
-                  | otherwise =
-                    snd $
-                    mapAccumL mk_qual d_Expr
+               where
+                 nm = occNameUserString (getOccName (fieldLabelName f))
+
+          field_quals
+             | is_infix  =
+                 snd (mapAccumL mk_qual_infix
+                                c_Expr
+                                [ (mk_read_qual lp as1, bs1, bs2)
+                                , (mk_read_qual rp as2, bs3, bs3)
+                                ])
+             | lab_fields == 0 =  -- common case.
+                 snd (mapAccumL mk_qual 
+                                d_Expr 
+                                (zipWithEqual "as_needed" 
+                                              (\ con_field draw_from -> (mk_read_qual 10 con_field,
+                                                                         draw_from))
+                                               as_needed bs_needed))
+              | otherwise =
+                 snd $
+                 mapAccumL mk_qual d_Expr
                        (zipEqual "bs_needed"        
                           ((str_qual "{":
                             concat (
@@ -835,36 +858,42 @@ gen_Read_binds tycon
                                    -- The labels
                                (map read_label labels)
                                    -- The fields
-                               (map mk_read_qual as_needed))) ++ [str_qual "}"])
+                               (map (mk_read_qual 10) as_needed))) ++ [str_qual "}"])
                            bs_needed)
 
-               mk_qual draw_from (f, str_left)
-                 = (HsVar str_left,    -- what to draw from down the line...
-                    f str_left draw_from)
+          mk_qual_infix draw_from (f, str_left, str_left2) =
+               (HsVar str_left2,       -- what to draw from down the line...
+                f str_left draw_from)
+
+          mk_qual draw_from (f, str_left) =
+               (HsVar str_left,        -- what to draw from down the line...
+                f str_left draw_from)
 
-               mk_read_qual con_field res draw_from =
-                 BindStmt
-                  (TuplePatIn [VarPatIn con_field, VarPatIn res] True)
-                  (HsApp (HsApp (HsVar readsPrec_RDR) (HsLit (HsInt 10))) draw_from)
-                  tycon_loc
+          mk_read_qual p con_field res draw_from =
+             BindStmt
+                (TuplePatIn [VarPatIn con_field, VarPatIn res] True)
+                (HsApp (HsApp (HsVar readsPrec_RDR) (HsLit (HsInt p))) draw_from)
+                tycon_loc
 
-               result_expr = ExplicitTuple [con_expr, if null bs_needed 
-                                                      then d_Expr 
-                                                      else HsVar (last bs_needed)] True
+          result_expr = ExplicitTuple [con_expr, if null bs_needed 
+                                                   then d_Expr 
+                                                   else HsVar (last bs_needed)] True
 
-               stmts = con_qual:field_quals ++ [ReturnStmt result_expr]
+           [lp,rp] = getLRPrecs fixities dc_nm
+
+           quals
+           | is_infix  = let (h:t) = field_quals in (h:con_qual:t)
+           | otherwise = con_qual:field_quals
+
+          stmts = quals ++ [ReturnStmt result_expr]
                
-               read_paren_arg
-                 = if nullary_con then -- must be False (parens are surely optional)
-                      false_Expr
-                   else -- parens depend on precedence...
-                      HsPar (genOpApp a_Expr gt_RDR (HsLit (HsInt 9)))
-           in
-           HsApp (
-             readParen_Expr read_paren_arg $ HsPar $
-                HsLam (mk_easy_Match tycon_loc [c_Pat] [] $
-                       HsDo ListComp stmts tycon_loc)
-             ) (HsVar b_RDR)
+          paren_prec_limit
+            | not is_infix  = 9
+            | otherwise     = getFixity fixities dc_nm
+
+          read_paren_arg   -- parens depend on precedence...
+           | nullary_con  = false_Expr -- it's optional.
+           | otherwise    = HsPar (genOpApp a_Expr gt_RDR (HsLit (HsInt paren_prec_limit)))
 
 \end{code}
 
@@ -874,12 +903,10 @@ gen_Read_binds tycon
 %*                                                                     *
 %************************************************************************
 
-Ignoring all the infix-ery mumbo jumbo (ToDo)
-
 \begin{code}
-gen_Show_binds :: TyCon -> RdrNameMonoBinds
+gen_Show_binds :: Fixities -> TyCon -> RdrNameMonoBinds
 
-gen_Show_binds tycon
+gen_Show_binds fixs_assoc tycon
   = shows_prec `AndMonoBinds` show_list
   where
     tycon_loc = getSrcLoc tycon
@@ -887,54 +914,75 @@ gen_Show_binds tycon
     show_list = mk_easy_FunMonoBind tycon_loc showList_RDR [] []
                  (HsApp (HsVar showList___RDR) (HsPar (HsApp (HsVar showsPrec_RDR) (HsLit (HsInt 0)))))
     -----------------------------------------------------------------------
-    shows_prec
-      = mk_FunMonoBind tycon_loc showsPrec_RDR (map pats_etc (tyConDataCons tycon))
+    shows_prec = mk_FunMonoBind tycon_loc showsPrec_RDR (map pats_etc (tyConDataCons tycon))
       where
        pats_etc data_con
-         = let
-               data_con_RDR = qual_orig_name data_con
-               con_arity    = argFieldCount data_con
-               bs_needed    = take con_arity bs_RDRs
-               con_pat      = ConPatIn data_con_RDR (map VarPatIn bs_needed)
-               nullary_con  = con_arity == 0
-                labels       = dataConFieldLabels data_con
-               lab_fields   = length labels
-
-               show_con
-                 = let nm = occNameUserString (getOccName data_con)
-                       space_ocurly_maybe
-                          | nullary_con     = ""
-                         | lab_fields == 0 = " "
-                         | otherwise       = "{"
-
-                   in
-                       mk_showString_app (nm ++ space_ocurly_maybe)
-
-               show_all con fs
-                 = let
-                        ccurly_maybe 
-                          | lab_fields > 0  = [mk_showString_app "}"]
-                          | otherwise       = []
-                   in
-                       con:fs ++ ccurly_maybe
-
-               show_thingies = show_all show_con real_show_thingies_with_labs
+         | nullary_con =  -- skip the showParen junk...
+            ASSERT(null bs_needed)
+            ([a_Pat, con_pat], show_con)
+         | otherwise   =
+            ([a_Pat, con_pat],
+                 showParen_Expr (HsPar (genOpApp a_Expr gt_RDR (HsLit (HsInt paren_prec_limit))))
+                                (HsPar (nested_compose_Expr show_thingies)))
+           where
+            data_con_RDR = qual_orig_name data_con
+            con_arity    = argFieldCount data_con
+            bs_needed    = take con_arity bs_RDRs
+            con_pat      = ConPatIn data_con_RDR (map VarPatIn bs_needed)
+            nullary_con  = con_arity == 0
+             labels       = dataConFieldLabels data_con
+            lab_fields   = length labels
+
+             dc_occ_nm    = occNameUserString (getOccName data_con)
+            dc_nm        = getName data_con
+
+            is_infix     = isInfixOccName dc_occ_nm
+
+
+            show_con
+              | is_infix  = mk_showString_app (' ':dc_occ_nm)
+              | otherwise =
+                let 
+                 space_ocurly_maybe
+                    | nullary_con     = ""
+                   | lab_fields == 0 = " "
+                   | otherwise       = "{"
+                in
+                mk_showString_app (dc_occ_nm ++ space_ocurly_maybe)
+
+            show_all con fs@(x:xs)
+               | is_infix  = x:con:xs
+               | otherwise = 
+                 let
+                    ccurly_maybe 
+                      | lab_fields > 0  = [mk_showString_app "}"]
+                      | otherwise       = []
+                 in
+                 con:fs ++ ccurly_maybe
+
+            show_thingies = show_all show_con real_show_thingies_with_labs
                 
-               show_label l 
-                 = let nm = occNameUserString (getOccName (fieldLabelName l)) 
-                   in
-                   mk_showString_app (nm ++ "=")
+            show_label l  = mk_showString_app (nm ++ "=")
+                where
+                  nm = occNameUserString (getOccName (fieldLabelName l))
+               
+
+             mk_showString_app str = HsApp (HsVar showString_RDR)
+                                          (HsLit (mkHsString str))
 
-                mk_showString_app str = HsApp (HsVar showString_RDR)
-                                             (HsLit (mkHsString str))
+             prec_cons = getLRPrecs fixs_assoc dc_nm
 
-               real_show_thingies =
+             real_show_thingies
+               | is_infix  = 
+                    [ HsApp (HsApp (HsVar showsPrec_RDR) (HsLit (HsInt p))) (HsVar b)
+                    | (p,b) <- zip prec_cons bs_needed ]
+               | otherwise =
                     [ HsApp (HsApp (HsVar showsPrec_RDR) (HsLit (HsInt 10))) (HsVar b)
                     | b <- bs_needed ]
 
-                real_show_thingies_with_labs
-                | lab_fields == 0 = intersperse (HsVar showSpace_RDR) real_show_thingies
-                | otherwise       = --Assumption: no of fields == no of labelled fields 
+             real_show_thingies_with_labs
+               | lab_fields == 0 = intersperse (HsVar showSpace_RDR) real_show_thingies
+               | otherwise       = --Assumption: no of fields == no of labelled fields 
                                     --            (and in same order)
                    concat $
                    intersperse ([mk_showString_app ","]) $ -- Using SLIT()s containing ,s spells trouble.
@@ -943,17 +991,52 @@ gen_Show_binds tycon
                                 (map show_label labels) 
                                 real_show_thingies
                               
+            (con_left_assoc, con_right_assoc) = isLRAssoc fixs_assoc dc_nm
+
+            paren_prec_limit
+               | not is_infix = 9
+               | otherwise    = getFixity fixs_assoc dc_nm
+
+\end{code}
+
+\begin{code}
+getLRPrecs :: Fixities -> Name -> [Integer]
+getLRPrecs fixs_assoc nm = [lp, rp]
+    where
+     ( con_left_assoc, con_right_assoc) = isLRAssoc fixs_assoc nm
+     paren_prec_limit = 9
+
+     lp
+      | con_left_assoc = paren_prec_limit
+      | otherwise      = paren_prec_limit + 1
+                 
+     rp
+      | con_right_assoc = paren_prec_limit
+      | otherwise       = paren_prec_limit + 1
+                 
+
+getFixity :: Fixities -> Name -> Integer
+getFixity fixs_assoc nm =
+  case assocMaybe fixs_assoc nm of
+     Nothing          -> 9
+     Just (Fixity x _) -> fromInt x + 1
+
+isLRAssoc :: Fixities -> Name -> (Bool, Bool)
+isLRAssoc fixs_assoc nm =
+     case assocMaybe fixs_assoc nm of
+       Just (Fixity _ InfixL) -> (True, False)
+       Just (Fixity _ InfixR) -> (False, True)
+       _                     -> (False, False)
+
+isInfixOccName :: String -> Bool
+isInfixOccName str = 
+   case str of
+     (':':_) -> True
+     _       -> False
 
-           in
-           if nullary_con then  -- skip the showParen junk...
-               ASSERT(null bs_needed)
-               ([a_Pat, con_pat], show_con)
-           else
-               ([a_Pat, con_pat],
-                   showParen_Expr (HsPar (genOpApp a_Expr ge_RDR (HsLit (HsInt 10))))
-                                  (HsPar (nested_compose_Expr show_thingies)))
 \end{code}
 
+
 %************************************************************************
 %*                                                                     *
 \subsection{Generating extra binds (@con2tag@ and @tag2con@)}
@@ -982,10 +1065,17 @@ gen_tag_n_con_monobind
     -> RdrNameMonoBinds
 
 gen_tag_n_con_monobind (rdr_name, tycon, GenCon2Tag)
+  | lots_of_constructors
+  = mk_FunMonoBind (getSrcLoc tycon) rdr_name 
+       [([VarPatIn a_RDR], HsApp getTag_Expr a_Expr)]
+
+  | otherwise
   = mk_FunMonoBind (getSrcLoc tycon) rdr_name (map mk_stuff (tyConDataCons tycon))
+
   where
-    mk_stuff :: DataCon -> ([RdrNamePat], RdrNameHsExpr)
+    lots_of_constructors = tyConFamilySize tycon > mAX_FAMILY_SIZE_FOR_VEC_RETURNS
 
+    mk_stuff :: DataCon -> ([RdrNamePat], RdrNameHsExpr)
     mk_stuff var
       = ([pat], HsLit (HsIntPrim (toInteger ((dataConTag var) - fIRST_TAG))))
       where
@@ -993,14 +1083,10 @@ gen_tag_n_con_monobind (rdr_name, tycon, GenCon2Tag)
        var_RDR = qual_orig_name var
 
 gen_tag_n_con_monobind (rdr_name, tycon, GenTag2Con)
-  = mk_FunMonoBind (getSrcLoc tycon) rdr_name (map mk_stuff (tyConDataCons tycon) ++ 
-                                                            [([WildPatIn], impossible_Expr)])
-  where
-    mk_stuff :: DataCon -> ([RdrNamePat], RdrNameHsExpr)
-    mk_stuff var = ([lit_pat], HsVar var_RDR)
-      where
-       lit_pat = ConPatIn mkInt_RDR [LitPatIn (HsIntPrim (toInteger ((dataConTag var) - fIRST_TAG)))]
-       var_RDR  = qual_orig_name var
+  = mk_FunMonoBind (getSrcLoc tycon) rdr_name 
+       [([ConPatIn mkInt_RDR [VarPatIn a_RDR]], 
+          ExprWithTySig (HsApp tagToEnum_Expr a_Expr) 
+                        (MonoTyVar (qual_orig_name tycon)))]
 
 gen_tag_n_con_monobind (rdr_name, tycon, GenMaxTag)
   = mk_easy_FunMonoBind (getSrcLoc tycon) 
@@ -1270,6 +1356,8 @@ gtTag_Expr        = HsVar gtTag_RDR
 false_Expr     = HsVar false_RDR
 true_Expr      = HsVar true_RDR
 
+getTag_Expr    = HsVar getTag_RDR
+tagToEnum_Expr         = HsVar tagToEnumH_RDR
 con2tag_Expr tycon = HsVar (con2tag_RDR tycon)
 
 a_Pat          = VarPatIn a_RDR