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Do the same initial transformations as for CFGs when generating FAs: remove cycles, identical rules and down top-down and bottom-up filtering.

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bringert
2007-03-20 22:00:50 +00:00
parent 4d369e096f
commit fe73354cc6
2 changed files with 11 additions and 7 deletions
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16
src/GF/Speech/CFGToFiniteState.hs
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@@ -59,11 +59,15 @@ data MFA a = MFA (DFA (MFALabel a)) [(String,DFA (MFALabel a))]
cfgToFA :: Options -> StateGrammar -> DFA String cfgToFA :: Options -> StateGrammar -> DFA String
cfgToFA opts s = minimize $ compileAutomaton start $ makeSimpleRegular s cfgToFA opts s = minimize $ compileAutomaton start $ makeSimpleRegular opts s
where start = getStartCatCF opts s where start = getStartCatCF opts s
makeSimpleRegular :: StateGrammar -> CFRules makeSimpleRegular :: Options -> StateGrammar -> CFRules
makeSimpleRegular = makeRegular . removeIdenticalRules . bottomUpFilter . cfgToCFRules makeSimpleRegular opts s = makeRegular $ preprocess $ cfgToCFRules s
where start = getStartCatCF opts s
preprocess = fix (topDownFilter start . bottomUpFilter)
. removeIdenticalRules
. removeCycles
-- --
-- * Approximate context-free grammars with regular grammars. -- * Approximate context-free grammars with regular grammars.
@@ -148,7 +152,7 @@ make_fa c@(g,ns) q0 alpha q1 fa =
-- --
cfgToMFA :: Options -> StateGrammar -> MFA String cfgToMFA :: Options -> StateGrammar -> MFA String
cfgToMFA opts s = buildMFA start s cfgToMFA opts s = buildMFA start $ makeSimpleRegular opts s
where start = getStartCatCF opts s where start = getStartCatCF opts s
-- | Build a DFA by building and expanding an MFA -- | Build a DFA by building and expanding an MFA
@@ -156,11 +160,11 @@ cfgToFA' :: Options -> StateGrammar -> DFA String
cfgToFA' opts s = mfaToDFA $ cfgToMFA opts s cfgToFA' opts s = mfaToDFA $ cfgToMFA opts s
buildMFA :: Cat_ -- ^ Start category buildMFA :: Cat_ -- ^ Start category
-> StateGrammar -> MFA String -> CFRules -> MFA String
buildMFA start g = sortSubLats $ removeUnusedSubLats mfa buildMFA start g = sortSubLats $ removeUnusedSubLats mfa
where startFA = let (fa,s,f) = newFA_ where startFA = let (fa,s,f) = newFA_
in newTransition s f (MFASub start) fa in newTransition s f (MFASub start) fa
fas = compileAutomata $ makeSimpleRegular g fas = compileAutomata g
mkMFALabel (Cat c) = MFASub c mkMFALabel (Cat c) = MFASub c
mkMFALabel (Tok t) = MFASym t mkMFALabel (Tok t) = MFASym t
toMFA = mapTransitions mkMFALabel toMFA = mapTransitions mkMFALabel

2
src/GF/Speech/PrFA.hs
View File

@@ -43,7 +43,7 @@ faGraphvizPrinter opts s =
-- | Convert the grammar to a regular grammar and print it in BNF -- | Convert the grammar to a regular grammar and print it in BNF
regularPrinter :: Options -> StateGrammar -> String regularPrinter :: Options -> StateGrammar -> String
regularPrinter opts s = prCFRules $ makeSimpleRegular s regularPrinter opts s = prCFRules $ makeSimpleRegular opts s
where where
prCFRules :: CFRules -> String prCFRules :: CFRules -> String
prCFRules g = unlines [ c ++ " ::= " ++ join " | " (map (showRhs . ruleRhs) rs) | (c,rs) <- g] prCFRules g = unlines [ c ++ " ::= " ++ join " | " (map (showRhs . ruleRhs) rs) | (c,rs) <- g]