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optimize certain pathological pattern matchings for strings

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krangelov
2021-12-14 09:16:40 +01:00
parent 9efb6b002f
commit 4886c7ce3b
1 changed files with 22 additions and 10 deletions
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32
src/compiler/GF/Compile/TypeCheck/Concrete.hs
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@@ -336,21 +336,33 @@ measurePatt gr p =
return (len,Just len,p)
PT t p -> do (min,max,p') <- measurePatt gr p
return (min,max,PT t p')
PAs x p -> do (min,max,p') <- measurePatt gr p
return (min,max,PAs x p')
PAs x p -> do (min,max,p) <- measurePatt gr p
case p of
PW -> return (0,Nothing,PV x)
_ -> return (min,max,PAs x p)
PImplArg p -> do (min,max,p') <- measurePatt gr p
return (min,max,PImplArg p')
PNeg p -> do (_,_,p') <- measurePatt gr p
return (0,Nothing,PNeg p')
PAlt p1 p2 -> do (min1,max1,p1') <- measurePatt gr p1
(min2,max2,p2') <- measurePatt gr p2
return (min min1 min2,liftM2 max max1 max2,PAlt p1' p2')
PAlt p1 p2 -> do (min1,max1,p1) <- measurePatt gr p1
(min2,max2,p2) <- measurePatt gr p2
case (p1,p2) of
(PString [c1],PString [c2]) -> return (1,Just 1,PChars [c1,c2])
(PString [c], PChars cs) -> return (1,Just 1,PChars ([c]++cs))
(PChars cs, PString [c]) -> return (1,Just 1,PChars (cs++[c]))
(PChars cs1, PChars cs2) -> return (1,Just 1,PChars (cs1++cs2))
_ -> return (min min1 min2,liftM2 max max1 max2,PAlt p1 p2)
PSeq _ _ p1 _ _ p2
-> do (min1,max1,p1') <- measurePatt gr p1
(min2,max2,p2') <- measurePatt gr p2
return (min1+min2,liftM2 (+) max1 max2,PSeq min1 max1 p1' min2 max2 p2')
PRep _ _ p -> do (minp,maxp,p') <- measurePatt gr p
return (0,Nothing,PRep minp maxp p')
-> do (min1,max1,p1) <- measurePatt gr p1
(min2,max2,p2) <- measurePatt gr p2
case (p1,p2) of
(PW,PW) -> return (0,Nothing,PW)
_ -> return (min1+min2,liftM2 (+) max1 max2,PSeq min1 max1 p1 min2 max2 p2)
PRep _ _ p -> do (minp,maxp,p) <- measurePatt gr p
case p of
PW -> return (0,Nothing,PW)
PChar -> return (0,Nothing,PW)
_ -> return (0,Nothing,PRep minp maxp p)
PChar -> return (1,Just 1,p)
PChars _ -> return (1,Just 1,p)
_ -> return (0,Nothing,p)