forked from GitHub/gf-core
Some tracing and formatting stuff looking for the the stack overflow problem in the FA generation.
This commit is contained in:
bringert
@@ -27,9 +27,13 @@ import GF.Speech.FiniteState
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import GF.Speech.Relation
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import GF.Speech.TransformCFG
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import Debug.Trace
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cfgToFA :: Options -> CGrammar -> DFA String
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cfgToFA opts = minimize . compileAutomaton start . makeSimpleRegular
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--cfgToFA opts = trfa "minimal" . minimize . trfa "initial" . compileAutomaton start . makeSimpleRegular
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where start = getStartCat opts
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trfa s fa = trace (s ++ ", states: " ++ show (length (states fa)) ++ ", transitions: " ++ show (length (transitions fa))) fa
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makeSimpleRegular :: CGrammar -> CFRules
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makeSimpleRegular = makeRegular . removeIdenticalRules . removeEmptyCats . cfgToCFRules
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@@ -41,74 +45,76 @@ makeSimpleRegular = makeRegular . removeIdenticalRules . removeEmptyCats . cfgTo
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makeRegular :: CFRules -> CFRules
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makeRegular g = groupProds $ concatMap trSet (mutRecCats True g)
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where trSet cs | allXLinear cs rs = rs
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| otherwise = concatMap handleCat cs
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where rs = catSetRules g cs
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handleCat c = [CFRule c' [] (mkName (c++"-empty"))] -- introduce A' -> e
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++ concatMap (makeRightLinearRules c) (catRules g c)
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where c' = newCat c
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makeRightLinearRules b' (CFRule c ss n) =
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case ys of
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[] -> [CFRule b' (xs ++ [Cat (newCat c)]) n] -- no non-terminals left
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(Cat b:zs) -> CFRule b' (xs ++ [Cat b]) n
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: makeRightLinearRules (newCat b) (CFRule c zs n)
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where (xs,ys) = break (`catElem` cs) ss
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newCat c = c ++ "$"
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| otherwise = concatMap handleCat cs
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where rs = catSetRules g cs
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handleCat c = [CFRule c' [] (mkName (c++"-empty"))] -- introduce A' -> e
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++ concatMap (makeRightLinearRules c) (catRules g c)
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where c' = newCat c
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makeRightLinearRules b' (CFRule c ss n) =
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case ys of
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[] -> [CFRule b' (xs ++ [Cat (newCat c)]) n] -- no non-terminals left
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(Cat b:zs) -> CFRule b' (xs ++ [Cat b]) n
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: makeRightLinearRules (newCat b) (CFRule c zs n)
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where (xs,ys) = break (`catElem` cs) ss
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newCat c = c ++ "$"
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-- | Get the sets of mutually recursive non-terminals for a grammar.
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mutRecCats :: Bool -- ^ If true, all categories will be in some set.
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-- If false, only recursive categories will be included.
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-> CFRules -> [[Cat_]]
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-> CFRules -> [[Cat_]]
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mutRecCats incAll g = equivalenceClasses $ refl $ symmetricSubrelation $ transitiveClosure r
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where r = mkRel [(c,c') | (_,rs) <- g, CFRule c ss _ <- rs, Cat c' <- ss]
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allCats = map fst g
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refl = if incAll then reflexiveClosure_ allCats else reflexiveSubrelation
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allCats = map fst g
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refl = if incAll then reflexiveClosure_ allCats else reflexiveSubrelation
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-- Convert a strongly regular grammar to a finite automaton.
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compileAutomaton :: Cat_ -- ^ Start category
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-> CFRules
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-> NFA Token
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-> CFRules
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-> NFA Token
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compileAutomaton start g = make_fa s [Cat start] f fa''
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where fa = newFA ()
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s = startState fa
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(fa',f) = newState () fa
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fa'' = addFinalState f fa'
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ns = mutRecCats False g
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-- | The make_fa algorithm from \"Regular approximation of CFLs: a grammatical view\",
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-- Mark-Jan Nederhof. International Workshop on Parsing Technologies, 1997.
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make_fa :: State -> [Symbol Cat_ Token] -> State
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-> NFA Token -> NFA Token
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make_fa q0 alpha q1 fa =
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case alpha of
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[] -> newTransition q0 q1 Nothing fa
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[Tok t] -> newTransition q0 q1 (Just t) fa
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[Cat a] -> case findSet a ns of
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-- a is recursive
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Just ni -> let (fa',ss) = addStatesForCats ni fa
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getState x = lookup' x ss
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niRules = catSetRules g ni
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(nrs,rs) = partition (ruleIsNonRecursive ni) niRules
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in if all (isRightLinear ni) niRules then
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-- the set Ni is right-recursive or cyclic
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let fa'' = foldFuns [make_fa (getState c) xs q1 | CFRule c xs _ <- nrs] fa'
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fa''' = foldFuns [make_fa (getState c) xs (getState d) | CFRule c ss _ <- rs,
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let (xs,Cat d) = (init ss,last ss)] fa''
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in newTransition q0 (getState a) Nothing fa'''
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else
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-- the set Ni is left-recursive
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let fa'' = foldFuns [make_fa q0 xs (getState c) | CFRule c xs _ <- nrs] fa'
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fa''' = foldFuns [make_fa (getState d) xs (getState c) | CFRule c (Cat d:xs) _ <- rs] fa''
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in newTransition (getState a) q1 Nothing fa'''
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-- a is not recursive
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Nothing -> let rs = catRules g a
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in foldl (\fa -> \ (CFRule _ b _) -> make_fa q0 b q1 fa) fa rs
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(x:beta) -> let (fa',q) = newState () fa
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in make_fa q beta q1 $ make_fa q0 [x] q fa'
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addStatesForCats [] fa = (fa,[])
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addStatesForCats (c:cs) fa = let (fa',s) = newState () fa
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(fa'',ss) = addStatesForCats cs fa'
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in (fa'',(c,s):ss)
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ruleIsNonRecursive cs = noCatsInSet cs . ruleRhs
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where
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fa = newFA ()
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s = startState fa
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(fa',f) = newState () fa
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fa'' = addFinalState f fa'
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ns = mutRecCats False g
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-- | The make_fa algorithm from \"Regular approximation of CFLs: a grammatical view\",
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-- Mark-Jan Nederhof. International Workshop on Parsing Technologies, 1997.
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make_fa :: State -> [Symbol Cat_ Token] -> State
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-> NFA Token -> NFA Token
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make_fa q0 alpha q1 fa =
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case alpha of
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[] -> newTransition q0 q1 Nothing fa
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[Tok t] -> newTransition q0 q1 (Just t) fa
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[Cat a] -> case findSet a ns of
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-- a is recursive
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Just ni -> let (fa',ss) = addStatesForCats ni fa
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getState x = lookup' x ss
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niRules = catSetRules g ni
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(nrs,rs) = partition (ruleIsNonRecursive ni) niRules
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in if all (isRightLinear ni) niRules
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then
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-- the set Ni is right-recursive or cyclic
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let fa'' = foldFuns [make_fa (getState c) xs q1 | CFRule c xs _ <- nrs] fa'
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fa''' = foldFuns [make_fa (getState c) xs (getState d) | CFRule c ss _ <- rs,
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let (xs,Cat d) = (init ss,last ss)] fa''
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in newTransition q0 (getState a) Nothing fa'''
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else
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-- the set Ni is left-recursive
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let fa'' = foldFuns [make_fa q0 xs (getState c) | CFRule c xs _ <- nrs] fa'
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fa''' = foldFuns [make_fa (getState d) xs (getState c) | CFRule c (Cat d:xs) _ <- rs] fa''
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in newTransition (getState a) q1 Nothing fa'''
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-- a is not recursive
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Nothing -> let rs = catRules g a
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in foldl (\fa -> \ (CFRule _ b _) -> make_fa q0 b q1 fa) fa rs
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(x:beta) -> let (fa',q) = newState () fa
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in make_fa q beta q1 $ make_fa q0 [x] q fa'
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addStatesForCats [] fa = (fa,[])
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addStatesForCats (c:cs) fa = let (fa',s) = newState () fa
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(fa'',ss) = addStatesForCats cs fa'
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in (fa'',(c,s):ss)
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ruleIsNonRecursive cs = noCatsInSet cs . ruleRhs
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noCatsInSet :: Eq c => [c] -> [Symbol c t] -> Bool
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@@ -121,12 +127,12 @@ allXLinear cs rs = all (isRightLinear cs) rs || all (isLeftLinear cs) rs
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-- | Checks if a context-free rule is right-linear.
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isRightLinear :: Eq c => [c] -- ^ The categories to consider
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-> CFRule c n t -- ^ The rule to check for right-linearity
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-> Bool
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-> CFRule c n t -- ^ The rule to check for right-linearity
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-> Bool
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isRightLinear cs = noCatsInSet cs . safeInit . ruleRhs
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-- | Checks if a context-free rule is left-linear.
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isLeftLinear :: Eq c => [c] -- ^ The categories to consider
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-> CFRule c n t -- ^ The rule to check for right-linearity
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-> Bool
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-> CFRule c n t -- ^ The rule to check for right-linearity
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-> Bool
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isLeftLinear cs = noCatsInSet cs . drop 1 . ruleRhs
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@@ -34,10 +34,13 @@ import Data.Char (toUpper,toLower)
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import Data.List
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import Data.Maybe (fromMaybe)
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faGraphvizPrinter :: Ident -- ^ Grammar name
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-> Options -> CGrammar -> String
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faGraphvizPrinter name opts cfg =
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prFAGraphviz $ mapStates (const "") $ cfgToFA opts cfg
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prFAGraphviz $ mapStates (const "") fa
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where fa = cfgToFA opts cfg
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-- | Convert the grammar to a regular grammar and print it in BNF
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