InPat(..),
OutPat(..),
- unfailablePats, unfailablePat,
+ irrefutablePat, irrefutablePats,
+ failureFreePat,
patsAreAllCons, isConPat,
patsAreAllLits, isLitPat,
- irrefutablePat,
collectPatBinders
) where
-import Ubiq
+IMP_Ubiq()
-- friends:
-import HsLit ( HsLit )
-import HsLoop ( HsExpr )
+-- IMPORT_DELOOPER(IdLoop)
+import HsBasic ( HsLit )
+import HsExpr ( HsExpr )
+import BasicTypes ( Fixity )
-- others:
-import Id ( GenId, dataConSig )
+import Id ( SYN_IE(Id), dataConTyCon, GenId )
import Maybes ( maybeToBool )
-import Name ( pprSym, pprNonSym )
-import Outputable ( interppSP, interpp'SP, ifPprShowAll )
-import PprStyle ( PprStyle(..) )
+import Outputable ( PprStyle(..), userStyle, interppSP,
+ interpp'SP, ifPprShowAll, Outputable(..)
+ )
import Pretty
import TyCon ( maybeTyConSingleCon )
import PprType ( GenType )
+import CmdLineOpts ( opt_PprUserLength )
+#if __GLASGOW_HASKELL__ >= 202
+import Name
+#endif
\end{code}
Patterns come in distinct before- and after-typechecking flavo(u)rs.
[InPat name]
| ConOpPatIn (InPat name)
name
+ Fixity -- c.f. OpApp in HsExpr
(InPat name)
+ | NPlusKPatIn name -- n+k pattern
+ HsLit
+
-- We preserve prefix negation and parenthesis for the precedence parser.
| NegPatIn (InPat name) -- negated pattern
[(name, InPat name, Bool)] -- True <=> source used punning
data OutPat tyvar uvar id
- = WildPat (GenType tyvar uvar) -- wild card
+ = WildPat (GenType tyvar uvar) -- wild card
| VarPat id -- variable (type is in the Id)
| ConPat Id -- Constructor is always an Id
(GenType tyvar uvar) -- the type of the pattern
- [(OutPat tyvar uvar id)]
+ [OutPat tyvar uvar id]
| ConOpPat (OutPat tyvar uvar id) -- just a special case...
Id
(GenType tyvar uvar)
| ListPat -- syntactic list
(GenType tyvar uvar) -- the type of the elements
- [(OutPat tyvar uvar id)]
+ [OutPat tyvar uvar id]
- | TuplePat [(OutPat tyvar uvar id)] -- tuple
+ | TuplePat [OutPat tyvar uvar id] -- tuple
-- UnitPat is TuplePat []
| RecPat Id -- record constructor
(HsExpr tyvar uvar id (OutPat tyvar uvar id))
-- of type t -> Bool; detects match
+ | NPlusKPat id
+ HsLit -- Same reason as for LitPat
+ -- (This could be an Integer, but then
+ -- it's harder to partitionEqnsByLit
+ -- in the desugarer.)
+ (GenType tyvar uvar) -- Type of pattern, t
+ (HsExpr tyvar uvar id (OutPat tyvar uvar id)) -- Of type t -> Bool; detects match
+ (HsExpr tyvar uvar id (OutPat tyvar uvar id)) -- Of type t -> t; subtracts k
+
| DictPat -- Used when destructing Dictionaries with an explicit case
[id] -- superclass dicts
[id] -- methods
instance (Outputable name, NamedThing name) => Outputable (InPat name) where
ppr = pprInPat
-pprInPat :: (Outputable name, NamedThing name) => PprStyle -> InPat name -> Pretty
+pprInPat :: (Outputable name, NamedThing name) => PprStyle -> InPat name -> Doc
-pprInPat sty (WildPatIn) = ppStr "_"
-pprInPat sty (VarPatIn var) = pprNonSym sty var
+pprInPat sty (WildPatIn) = char '_'
+pprInPat sty (VarPatIn var) = ppr sty var
pprInPat sty (LitPatIn s) = ppr sty s
-pprInPat sty (LazyPatIn pat) = ppBeside (ppChar '~') (ppr sty pat)
+pprInPat sty (LazyPatIn pat) = (<>) (char '~') (ppr sty pat)
pprInPat sty (AsPatIn name pat)
- = ppBesides [ppLparen, ppr sty name, ppChar '@', ppr sty pat, ppRparen]
+ = parens (hcat [ppr sty name, char '@', ppr sty pat])
pprInPat sty (ConPatIn c pats)
= if null pats then
ppr sty c
else
- ppBesides [ppLparen, ppr sty c, ppSP, interppSP sty pats, ppRparen]
+ hsep [ppr sty c, interppSP sty pats] -- ParPats put in the parens
-
-pprInPat sty (ConOpPatIn pat1 op pat2)
- = ppBesides [ppLparen, ppr sty pat1, ppSP, ppr sty op, ppSP, ppr sty pat2, ppRparen]
+pprInPat sty (ConOpPatIn pat1 op fixity pat2)
+ = hsep [ppr sty pat1, ppr sty op, ppr sty pat2] -- ParPats put in parens
-- ToDo: use pprSym to print op (but this involves fiddling various
-- contexts & I'm lazy...); *PatIns are *rarely* printed anyway... (WDP)
= let
pp_pat = pprInPat sty pat
in
- ppBeside (ppChar '-') (
+ (<>) (char '-') (
case pat of
LitPatIn _ -> pp_pat
- _ -> ppParens pp_pat
+ _ -> parens pp_pat
)
pprInPat sty (ParPatIn pat)
- = ppParens (pprInPat sty pat)
+ = parens (pprInPat sty pat)
pprInPat sty (ListPatIn pats)
- = ppBesides [ppLbrack, interpp'SP sty pats, ppRbrack]
+ = brackets (interpp'SP sty pats)
pprInPat sty (TuplePatIn pats)
- = ppBesides [ppLparen, interpp'SP sty pats, ppRparen]
+ = parens (interpp'SP sty pats)
+pprInPat sty (NPlusKPatIn n k)
+ = parens (hcat [ppr sty n, char '+', ppr sty k])
pprInPat sty (RecPatIn con rpats)
- = ppBesides [ppr sty con, ppSP, ppChar '{', ppInterleave ppComma (map (pp_rpat sty) rpats), ppChar '}']
+ = hsep [ppr sty con, braces (hsep (punctuate comma (map (pp_rpat sty) rpats)))]
where
- pp_rpat PprForUser (v, _, True) = ppr PprForUser v
- pp_rpat sty (v, p, _) = ppCat [ppr sty v, ppStr "=", ppr sty p]
+ pp_rpat sty (v, _, True) | userStyle sty = ppr (PprForUser opt_PprUserLength) v
+ pp_rpat sty (v, p, _) = hsep [ppr sty v, char '=', ppr sty p]
\end{code}
\begin{code}
-instance (Eq tyvar, Outputable tyvar, Eq uvar, Outputable uvar,
- NamedThing id, Outputable id)
+instance (Eq tyvar, Outputable tyvar, Eq uvar, Outputable uvar, Outputable id)
=> Outputable (OutPat tyvar uvar id) where
ppr = pprOutPat
\end{code}
\begin{code}
-pprOutPat sty (WildPat ty) = ppChar '_'
-pprOutPat sty (VarPat var) = pprNonSym sty var
-pprOutPat sty (LazyPat pat) = ppBesides [ppChar '~', ppr sty pat]
+pprOutPat sty (WildPat ty) = char '_'
+pprOutPat sty (VarPat var) = ppr sty var
+pprOutPat sty (LazyPat pat) = hcat [char '~', ppr sty pat]
pprOutPat sty (AsPat name pat)
- = ppBesides [ppLparen, ppr sty name, ppChar '@', ppr sty pat, ppRparen]
+ = parens (hcat [ppr sty name, char '@', ppr sty pat])
pprOutPat sty (ConPat name ty [])
- = ppBeside (ppr sty name)
+ = (<>) (ppr sty name)
(ifPprShowAll sty (pprConPatTy sty ty))
pprOutPat sty (ConPat name ty pats)
- = ppBesides [ppLparen, ppr sty name, ppSP,
- interppSP sty pats, ppRparen,
- ifPprShowAll sty (pprConPatTy sty ty) ]
+ = hcat [parens (hcat [ppr sty name, space, interppSP sty pats]),
+ ifPprShowAll sty (pprConPatTy sty ty) ]
pprOutPat sty (ConOpPat pat1 op pat2 ty)
- = ppBesides [ppLparen, ppr sty pat1, ppSP, pprSym sty op, ppSP, ppr sty pat2, ppRparen]
+ = parens (hcat [ppr sty pat1, space, ppr sty op, space, ppr sty pat2])
pprOutPat sty (ListPat ty pats)
- = ppBesides [ppLbrack, interpp'SP sty pats, ppRbrack]
+ = brackets (interpp'SP sty pats)
pprOutPat sty (TuplePat pats)
- = ppBesides [ppLparen, interpp'SP sty pats, ppRparen]
+ = parens (interpp'SP sty pats)
pprOutPat sty (RecPat con ty rpats)
- = ppBesides [ppr sty con, ppChar '{', ppInterleave ppComma (map (pp_rpat sty) rpats), ppChar '}']
+ = hcat [ppr sty con, braces (hsep (punctuate comma (map (pp_rpat sty) rpats)))]
where
- pp_rpat PprForUser (v, _, True) = ppr PprForUser v
- pp_rpat sty (v, p, _) = ppCat [ppr sty v, ppStr "=", ppr sty p]
+ pp_rpat sty (v, _, True) | userStyle sty = ppr (PprForUser opt_PprUserLength) v
+ pp_rpat sty (v, p, _) = hsep [ppr sty v, char '=', ppr sty p]
pprOutPat sty (LitPat l ty) = ppr sty l -- ToDo: print more
pprOutPat sty (NPat l ty e) = ppr sty l -- ToDo: print more
+pprOutPat sty (NPlusKPat n k ty e1 e2) -- ToDo: print more
+ = parens (hcat [ppr sty n, char '+', ppr sty k])
pprOutPat sty (DictPat dicts methods)
- = ppSep [ppBesides [ppLparen, ppPStr SLIT("{-dict-}")],
- ppBracket (interpp'SP sty dicts),
- ppBesides [ppBracket (interpp'SP sty methods), ppRparen]]
+ = parens (sep [ptext SLIT("{-dict-}"),
+ brackets (interpp'SP sty dicts),
+ brackets (interpp'SP sty methods)])
pprConPatTy sty ty
- = ppParens (ppr sty ty)
+ = parens (ppr sty ty)
\end{code}
%************************************************************************
A pattern is in {\em exactly one} of the above three categories; `as'
patterns are treated specially, of course.
+The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are.
\begin{code}
-unfailablePats :: [OutPat a b c] -> Bool
-unfailablePats pat_list = all unfailablePat pat_list
-
-unfailablePat (AsPat _ pat) = unfailablePat pat
-unfailablePat (WildPat _) = True
-unfailablePat (VarPat _) = True
-unfailablePat (LazyPat _) = True
-unfailablePat (DictPat ds ms) = (length ds + length ms) <= 1
-unfailablePat other = False
+irrefutablePats :: [OutPat a b c] -> Bool
+irrefutablePats pat_list = all irrefutablePat pat_list
+
+irrefutablePat (AsPat _ pat) = irrefutablePat pat
+irrefutablePat (WildPat _) = True
+irrefutablePat (VarPat _) = True
+irrefutablePat (LazyPat _) = True
+irrefutablePat (DictPat ds ms) = (length ds + length ms) <= 1
+irrefutablePat other = False
+
+failureFreePat :: OutPat a b c -> 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 (ListPat _ _) = False
+failureFreePat (TuplePat pats) = all failureFreePat pats
+failureFreePat (DictPat _ _) = True
+failureFreePat other_pat = False -- Literals, NPat
+
+only_con con = maybeToBool (maybeTyConSingleCon (dataConTyCon con))
+\end{code}
+\begin{code}
patsAreAllCons :: [OutPat a b c] -> Bool
patsAreAllCons pat_list = all isConPat pat_list
isConPat (ConOpPat _ _ _ _) = True
isConPat (ListPat _ _) = True
isConPat (TuplePat _) = True
+isConPat (RecPat _ _ _) = True
isConPat (DictPat ds ms) = (length ds + length ms) > 1
isConPat other = False
patsAreAllLits :: [OutPat a b c] -> Bool
patsAreAllLits pat_list = all isLitPat pat_list
-isLitPat (AsPat _ pat) = isLitPat pat
-isLitPat (LitPat _ _) = True
-isLitPat (NPat _ _ _) = True
-isLitPat other = False
-\end{code}
-
-A pattern is irrefutable if a match on it cannot fail
-(at any depth).
-\begin{code}
-irrefutablePat :: OutPat a b c -> Bool
-
-irrefutablePat (WildPat _) = True
-irrefutablePat (VarPat _) = True
-irrefutablePat (LazyPat _) = True
-irrefutablePat (AsPat _ pat) = irrefutablePat pat
-irrefutablePat (ConPat con tys pats) = all irrefutablePat pats && only_con con
-irrefutablePat (ConOpPat pat1 con pat2 _) = irrefutablePat pat1 && irrefutablePat pat1 && only_con con
-irrefutablePat (ListPat _ _) = False
-irrefutablePat (TuplePat pats) = all irrefutablePat pats
-irrefutablePat (DictPat _ _) = True
-irrefutablePat other_pat = False -- Literals, NPat
-
-only_con con = maybeToBool (maybeTyConSingleCon tycon)
- where
- (_,_,_,tycon) = dataConSig con
+isLitPat (AsPat _ pat) = isLitPat pat
+isLitPat (LitPat _ _) = True
+isLitPat (NPat _ _ _) = True
+isLitPat (NPlusKPat _ _ _ _ _) = True
+isLitPat other = False
\end{code}
This function @collectPatBinders@ works with the ``collectBinders''
\begin{code}
collectPatBinders :: InPat a -> [a]
-collectPatBinders WildPatIn = []
-collectPatBinders (VarPatIn var) = [var]
-collectPatBinders (LazyPatIn pat) = collectPatBinders pat
-collectPatBinders (AsPatIn a pat) = a : collectPatBinders pat
-collectPatBinders (ConPatIn c pats) = concat (map collectPatBinders pats)
-collectPatBinders (ConOpPatIn p1 c 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 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)
\end{code}
projects / ghc-hetmet.git / blobdiff