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compilation of pattern matching using the algorithm of Lennart Augustsson. Not used yet

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krasimir
2010-06-30 16:00:47 +00:00
parent 97a9ddb4a7
commit 3a5f193fd7
1 changed files with 19 additions and 0 deletions
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19
src/compiler/GF/Compile/GrammarToPGF.hs
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@@ -127,6 +127,25 @@ mkDef Nothing = Nothing
mkArrity (Just a) = a
mkArrity Nothing = 0
data PattTree
= Ret C.Expr
| Case (Map.Map QIdent [PattTree]) [PattTree]
compilePatt :: [Equation] -> [PattTree]
compilePatt (([],t):_) = [Ret (mkExp [] t)]
compilePatt eqs = whilePP eqs Map.empty
where
whilePP [] cns = [mkCase cns []]
whilePP (((PP c ps' : ps), t):eqs) cns = whilePP eqs (Map.insertWith (++) c [(ps'++ps,t)] cns)
whilePP eqs cns = whilePV eqs cns []
whilePV [] cns vrs = [mkCase cns (reverse vrs)]
whilePV (((PV x : ps), t):eqs) cns vrs = whilePV eqs cns ((ps,t) : vrs)
whilePV eqs cns vrs = mkCase cns (reverse vrs) : compilePatt eqs
mkCase cns vrs = Case (fmap compilePatt cns) (compilePatt vrs)
-- return just one module per language
reorder :: Ident -> SourceGrammar -> SourceGrammar