%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[PatSyntax]{Abstract Haskell syntax---patterns}
OutPat(..),
irrefutablePat, irrefutablePats,
- failureFreePat,
+ failureFreePat, isWildPat,
patsAreAllCons, isConPat,
patsAreAllLits, isLitPat,
- collectPatBinders
+ collectPatBinders, collectPatsBinders
) where
#include "HsVersions.h"
-- friends:
import HsBasic ( HsLit )
import HsExpr ( HsExpr )
-import BasicTypes ( Fixity )
+import HsTypes ( HsType )
+import BasicTypes ( Fixity, Boxity, tupleParens )
-- others:
-import Id ( Id, dataConTyCon, GenId )
+import Var ( Id, TyVar )
+import DataCon ( DataCon, dataConTyCon )
+import Name ( isDataSymOcc, getOccName, NamedThing )
import Maybes ( maybeToBool )
import Outputable
import TyCon ( maybeTyConSingleCon )
-import PprType ( GenType )
-import Name ( NamedThing )
+import Type ( Type )
\end{code}
Patterns come in distinct before- and after-typechecking flavo(u)rs.
| LazyPatIn (InPat name) -- lazy pattern
| AsPatIn name -- as pattern
(InPat name)
+ | SigPatIn (InPat name)
+ (HsType name)
| ConPatIn name -- constructed type
[InPat name]
| ConOpPatIn (InPat name)
| ListPatIn [InPat name] -- syntactic list
-- must have >= 1 elements
- | TuplePatIn [InPat name] -- tuple
+ | TuplePatIn [InPat name] Boxity -- tuple (boxed?)
| RecPatIn name -- record
[(name, InPat name, Bool)] -- True <=> source used punning
-data OutPat flexi id
- = WildPat (GenType flexi) -- wild card
+data OutPat id
+ = WildPat Type -- wild card
+ | VarPat id -- variable (type is in the Id)
+ | LazyPat (OutPat id) -- lazy pattern
+ | AsPat id -- as pattern
+ (OutPat id)
- | VarPat id -- variable (type is in the Id)
+ | ListPat -- syntactic list
+ Type -- the type of the elements
+ [OutPat id]
- | LazyPat (OutPat flexi id) -- lazy pattern
-
- | AsPat id -- as pattern
- (OutPat flexi id)
-
- | ConPat Id -- Constructor is always an Id
- (GenType flexi) -- the type of the pattern
- [OutPat flexi id]
+ | TuplePat [OutPat id] -- tuple
+ Boxity
+ -- UnitPat is TuplePat []
- | ConOpPat (OutPat flexi id) -- just a special case...
- Id
- (OutPat flexi id)
- (GenType flexi)
- | ListPat -- syntactic list
- (GenType flexi) -- the type of the elements
- [OutPat flexi id]
+ | ConPat DataCon
+ Type -- the type of the pattern
+ [TyVar] -- Existentially bound type variables
+ [id] -- Ditto dictionaries
+ [OutPat id]
- | TuplePat [OutPat flexi id] -- tuple
- -- UnitPat is TuplePat []
+ -- ConOpPats are only used on the input side
- | RecPat Id -- record constructor
- (GenType flexi) -- the type of the pattern
- [(Id, OutPat flexi id, Bool)] -- True <=> source used punning
+ | RecPat DataCon -- record constructor
+ Type -- the type of the pattern
+ [TyVar] -- Existentially bound type variables
+ [id] -- Ditto dictionaries
+ [(Id, OutPat id, Bool)] -- True <=> source used punning
| LitPat -- Used for *non-overloaded* literal patterns:
-- Int#, Char#, Int, Char, String, etc.
HsLit
- (GenType flexi) -- type of pattern
+ Type -- type of pattern
| NPat -- Used for *overloaded* literal patterns
HsLit -- the literal is retained so that
-- the desugarer can readily identify
-- equations with identical literal-patterns
- (GenType flexi) -- type of pattern, t
- (HsExpr flexi id (OutPat flexi id))
+ Type -- type of pattern, t
+ (HsExpr id (OutPat id))
-- of type t -> Bool; detects match
| NPlusKPat id
-- (This could be an Integer, but then
-- it's harder to partitionEqnsByLit
-- in the desugarer.)
- (GenType flexi) -- Type of pattern, t
- (HsExpr flexi id (OutPat flexi id)) -- Of type t -> Bool; detects match
- (HsExpr flexi id (OutPat flexi id)) -- Of type t -> t; subtracts k
+ Type -- Type of pattern, t
+ (HsExpr id (OutPat id)) -- Of type t -> Bool; detects match
+ (HsExpr id (OutPat id)) -- Of type t -> t; subtracts k
| DictPat -- Used when destructing Dictionaries with an explicit case
[id] -- superclass dicts
pprInPat (WildPatIn) = char '_'
pprInPat (VarPatIn var) = ppr var
pprInPat (LitPatIn s) = ppr s
+pprInPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty
pprInPat (LazyPatIn pat) = char '~' <> ppr pat
pprInPat (AsPatIn name pat) = parens (hcat [ppr name, char '@', ppr pat])
pprInPat (ConPatIn c pats)
| null pats = ppr c
- | otherwise = hsep [ppr c, interppSP pats] -- ParPats put in the parens
+ | otherwise = hsep [ppr c, interppSP pats] -- inner ParPats supply the necessary parens.
pprInPat (ConOpPatIn pat1 op fixity pat2)
= hsep [ppr pat1, ppr op, ppr pat2] -- ParPats put in parens
pprInPat (ListPatIn pats)
= brackets (interpp'SP pats)
-pprInPat (TuplePatIn pats)
- = parens (interpp'SP pats)
+pprInPat (TuplePatIn pats boxity)
+ = tupleParens boxity (interpp'SP pats)
pprInPat (NPlusKPatIn n k)
= parens (hcat [ppr n, char '+', ppr k])
\end{code}
\begin{code}
-instance (Outputable id) => Outputable (OutPat flexi id) where
+instance (NamedThing id, Outputable id) => Outputable (OutPat id) where
ppr = pprOutPat
\end{code}
pprOutPat (AsPat name pat)
= parens (hcat [ppr name, char '@', ppr pat])
-pprOutPat (ConPat name ty [])
+pprOutPat (ConPat name ty [] [] [])
= ppr name
-pprOutPat (ConPat name ty pats)
- = hcat [parens (hcat [ppr name, space, interppSP pats])]
-
-pprOutPat (ConOpPat pat1 op pat2 ty)
- = parens (hcat [ppr pat1, space, ppr op, space, ppr pat2])
-
-pprOutPat (ListPat ty pats)
- = brackets (interpp'SP pats)
-pprOutPat (TuplePat pats)
- = parens (interpp'SP pats)
-
-pprOutPat (RecPat con ty rpats)
- = hcat [ppr con, braces (hsep (punctuate comma (map (pp_rpat) rpats)))]
+-- Kludge to get infix constructors to come out right
+-- when ppr'ing desugar warnings.
+pprOutPat (ConPat name ty tyvars dicts pats)
+ = getPprStyle $ \ sty ->
+ parens $
+ case pats of
+ [p1,p2]
+ | userStyle sty && isDataSymOcc (getOccName name) ->
+ hsep [ppr p1, ppr name, ppr p2]
+ _ -> hsep [ppr name, interppSP tyvars, interppSP dicts, interppSP pats]
+
+pprOutPat (ListPat ty pats) = brackets (interpp'SP pats)
+pprOutPat (TuplePat pats boxity) = tupleParens boxity (interpp'SP pats)
+
+pprOutPat (RecPat con ty tvs dicts rpats)
+ = hsep [ppr con, interppSP tvs, interppSP dicts, braces (hsep (punctuate comma (map (pp_rpat) rpats)))]
where
pp_rpat (v, _, True) = ppr v
pp_rpat (v, p, _) = hsep [ppr v, char '=', ppr p]
brackets (interpp'SP dicts),
brackets (interpp'SP methods)])
-pprConPatTy ty
- = parens (ppr ty)
\end{code}
%************************************************************************
The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are.
\begin{code}
-irrefutablePats :: [OutPat a b] -> Bool
+irrefutablePats :: [OutPat id] -> Bool
irrefutablePats pat_list = all irrefutablePat pat_list
irrefutablePat (AsPat _ pat) = irrefutablePat pat
irrefutablePat (DictPat ds ms) = (length ds + length ms) <= 1
irrefutablePat other = False
-failureFreePat :: OutPat a b -> Bool
+failureFreePat :: OutPat id -> Bool
failureFreePat (WildPat _) = True
failureFreePat (VarPat _) = True
failureFreePat (LazyPat _) = True
failureFreePat (AsPat _ pat) = failureFreePat pat
-failureFreePat (ConPat con tys pats) = only_con con && all failureFreePat pats
-failureFreePat (ConOpPat pat1 con pat2 _) = only_con con && failureFreePat pat1 && failureFreePat pat1
-failureFreePat (RecPat con _ fields) = only_con con && and [ failureFreePat pat | (_,pat,_) <- fields ]
+failureFreePat (ConPat con tys _ _ pats) = only_con con && all failureFreePat pats
+failureFreePat (RecPat con _ _ _ fields) = only_con con && and [ failureFreePat pat | (_,pat,_) <- fields ]
failureFreePat (ListPat _ _) = False
-failureFreePat (TuplePat pats) = all failureFreePat pats
+failureFreePat (TuplePat pats _) = all failureFreePat pats
failureFreePat (DictPat _ _) = True
failureFreePat other_pat = False -- Literals, NPat
\end{code}
\begin{code}
-patsAreAllCons :: [OutPat a b] -> Bool
+isWildPat (WildPat _) = True
+isWildPat other = False
+
+patsAreAllCons :: [OutPat id] -> Bool
patsAreAllCons pat_list = all isConPat pat_list
isConPat (AsPat _ pat) = isConPat pat
-isConPat (ConPat _ _ _) = True
-isConPat (ConOpPat _ _ _ _) = True
+isConPat (ConPat _ _ _ _ _) = True
isConPat (ListPat _ _) = True
-isConPat (TuplePat _) = True
-isConPat (RecPat _ _ _) = True
+isConPat (TuplePat _ _) = True
+isConPat (RecPat _ _ _ _ _) = True
isConPat (DictPat ds ms) = (length ds + length ms) > 1
isConPat other = False
-patsAreAllLits :: [OutPat a b] -> Bool
+patsAreAllLits :: [OutPat id] -> Bool
patsAreAllLits pat_list = all isLitPat pat_list
isLitPat (AsPat _ pat) = isLitPat pat
This function @collectPatBinders@ works with the ``collectBinders''
functions for @HsBinds@, etc. The order in which the binders are
collected is important; see @HsBinds.lhs@.
+
\begin{code}
collectPatBinders :: InPat a -> [a]
-
-collectPatBinders WildPatIn = []
-collectPatBinders (VarPatIn var) = [var]
-collectPatBinders (LitPatIn _) = []
-collectPatBinders (LazyPatIn pat) = collectPatBinders pat
-collectPatBinders (AsPatIn a pat) = a : collectPatBinders pat
-collectPatBinders (NPlusKPatIn n _) = [n]
-collectPatBinders (ConPatIn c pats) = concat (map collectPatBinders pats)
-collectPatBinders (ConOpPatIn p1 c f p2) = collectPatBinders p1 ++ collectPatBinders p2
-collectPatBinders (NegPatIn pat) = collectPatBinders pat
-collectPatBinders (ParPatIn pat) = collectPatBinders pat
-collectPatBinders (ListPatIn pats) = concat (map collectPatBinders pats)
-collectPatBinders (TuplePatIn pats) = concat (map collectPatBinders pats)
-collectPatBinders (RecPatIn c fields) = concat (map (\ (f,pat,_) -> collectPatBinders pat) fields)
+collectPatBinders pat = collect pat []
+
+collectPatsBinders :: [InPat a] -> [a]
+collectPatsBinders pats = foldr collect [] pats
+
+collect WildPatIn bndrs = bndrs
+collect (VarPatIn var) bndrs = var : bndrs
+collect (LitPatIn _) bndrs = bndrs
+collect (SigPatIn pat _) bndrs = collect pat bndrs
+collect (LazyPatIn pat) bndrs = collect pat bndrs
+collect (AsPatIn a pat) bndrs = a : collect pat bndrs
+collect (NPlusKPatIn n _) bndrs = n : bndrs
+collect (ConPatIn c pats) bndrs = foldr collect bndrs pats
+collect (ConOpPatIn p1 c f p2) bndrs = collect p1 (collect p2 bndrs)
+collect (NegPatIn pat) bndrs = collect pat bndrs
+collect (ParPatIn pat) bndrs = collect pat bndrs
+collect (ListPatIn pats) bndrs = foldr collect bndrs pats
+collect (TuplePatIn pats _) bndrs = foldr collect bndrs pats
+collect (RecPatIn c fields) bndrs = foldr (\ (f,pat,_) bndrs -> collect pat bndrs) bndrs fields
\end{code}
projects / ghc-hetmet.git / blobdiff