Parametrized the type of FAs over the state type.

This commit is contained in:
bringert
2005-09-14 15:08:35 +00:00
parent ffe99a1474
commit 0916a479d8
3 changed files with 70 additions and 71 deletions

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@@ -5,9 +5,9 @@
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/09/14 15:17:29 $
-- > CVS $Date: 2005/09/14 16:08:35 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.3 $
-- > CVS $Revision: 1.4 $
--
-- Approximates CFGs with finite state networks.
-----------------------------------------------------------------------------
@@ -27,7 +27,7 @@ import GF.Speech.FiniteState
import GF.Speech.TransformCFG
cfgToFA :: Ident -- ^ Grammar name
-> Options -> CGrammar -> FA () (Maybe String)
-> Options -> CGrammar -> NFA String
cfgToFA name opts = minimize . compileAutomaton start . makeSimpleRegular
where start = getStartCat opts
@@ -67,7 +67,7 @@ mutRecCats incAll g = equivalenceClasses $ symmetricSubrelation $ transitiveClos
-- Convert a strongly regular grammar to a finite automaton.
compileAutomaton :: Cat_ -- ^ Start category
-> CFRules
-> FA () (Maybe Token)
-> NFA Token
compileAutomaton start g = make_fa s [Cat start] f fa''
where fa = newFA ()
s = startState fa
@@ -77,7 +77,7 @@ compileAutomaton start g = make_fa s [Cat start] f fa''
-- | The make_fa algorithm from \"Regular approximation of CFLs: a grammatical view\",
-- Mark-Jan Nederhof. International Workshop on Parsing Technologies, 1997.
make_fa :: State -> [Symbol Cat_ Token] -> State
-> FA () (Maybe Token) -> FA () (Maybe Token)
-> NFA Token -> NFA Token
make_fa q0 alpha q1 fa =
case alpha of
[] -> newTransition q0 q1 Nothing fa

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@@ -5,13 +5,13 @@
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/09/14 15:29:53 $
-- > CVS $Date: 2005/09/14 16:08:35 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.8 $
-- > CVS $Revision: 1.9 $
--
-- A simple finite state network module.
-----------------------------------------------------------------------------
module GF.Speech.FiniteState (FA, State,
module GF.Speech.FiniteState (FA, State, NFA, DFA,
startState, finalStates,
states, transitions,
newFA,
@@ -22,71 +22,106 @@ module GF.Speech.FiniteState (FA, State,
prFAGraphviz) where
import Data.List
import Data.Maybe (fromJust)
import Data.Maybe (catMaybes,fromJust)
import GF.Data.Utilities
import qualified GF.Visualization.Graphviz as Dot
type State = Int
data FA a b = FA (Graph State a b) State [State]
data FA n a b = FA (Graph n a b) n [n]
type State = Node
type NFA a = FA State () (Maybe a)
startState :: FA a b -> State
type DFA a = FA [State] () a
startState :: FA n a b -> n
startState (FA _ s _) = s
finalStates :: FA a b -> [State]
finalStates :: FA n a b -> [n]
finalStates (FA _ _ ss) = ss
states :: FA a b -> [(State,a)]
states :: FA n a b -> [(n,a)]
states (FA g _ _) = nodes g
transitions :: FA a b -> [(State,State,b)]
transitions :: FA n a b -> [(n,n,b)]
transitions (FA g _ _) = edges g
newFA :: a -- ^ Start node label
-> FA a b
newFA :: Enum n => a -- ^ Start node label
-> FA n a b
newFA l = FA g s []
where (g,s) = newNode l (newGraph [0..])
where (g,s) = newNode l (newGraph [toEnum 0..])
addFinalState :: State -> FA a b -> FA a b
addFinalState :: n -> FA n a b -> FA n a b
addFinalState f (FA g s ss) = FA g s (f:ss)
newState :: a -> FA a b -> (FA a b, State)
newState :: a -> FA n a b -> (FA n a b, n)
newState x (FA g s ss) = (FA g' s ss, n)
where (g',n) = newNode x g
newTransition :: State -> State -> b -> FA a b -> FA a b
newTransition :: n -> n -> b -> FA n a b -> FA n a b
newTransition f t l = onGraph (newEdge f t l)
mapStates :: (a -> c) -> FA a b -> FA c b
mapStates :: (a -> c) -> FA n a b -> FA n c b
mapStates f = onGraph (nmap f)
mapTransitions :: (b -> c) -> FA a b -> FA a c
mapTransitions :: (b -> c) -> FA n a b -> FA n a c
mapTransitions f = onGraph (emap f)
minimize :: FA () (Maybe a) -> FA () (Maybe a)
minimize = onGraph mimimizeGr1
minimize :: NFA a -> NFA a
minimize = onGraph id
onGraph :: (Graph State a b -> Graph State c d) -> FA a b -> FA c d
onGraph :: (Graph n a b -> Graph n c d) -> FA n a b -> FA n c d
onGraph f (FA g s ss) = FA (f g) s ss
-- | Transform a standard finite automaton with labelled edges
-- to one where the labels are on the nodes instead. This can add
-- up to one extra node per edge.
moveLabelsToNodes :: Eq a => FA () (Maybe a) -> FA (Maybe a) ()
moveLabelsToNodes :: (Ord n,Eq a) => FA n () (Maybe a) -> FA n (Maybe a) ()
moveLabelsToNodes = onGraph moveLabelsToNodes_
where moveLabelsToNodes_ gr@(Graph c _ _) = Graph c' (zip ns ls) (concat ess)
where is = incoming gr
(c',is') = mapAccumL fixIncoming c is
(ns,ls,ess) = unzip3 (concat is')
prFAGraphviz :: FA String String -> String
prFAGraphviz = Dot.prGraphviz . mkGraphviz
where
mkGraphviz (FA (Graph _ ns es) s f) = Dot.Graph Dot.Directed [] (map mkNode ns) (map mkEdge es)
fixIncoming :: (Eq n, Eq a) => [n] -> (n,(),[(n,n,Maybe a)]) -> ([n],[(n,Maybe a,[(n,n,())])])
fixIncoming cs c@(n,(),es) = (cs'', (n,Nothing,es'):newContexts)
where ls = nub $ map getLabel es
(cs',cs'') = splitAt (length ls) cs
newNodes = zip cs' ls
es' = [ (x,n,()) | x <- map fst newNodes ]
-- separate cyclic and non-cyclic edges
(cyc,ncyc) = partition (\ (f,_,_) -> f == n) es
-- keep all incoming non-cyclic edges with the right label
to x l = [ (f,x,()) | (f,_,l') <- ncyc, l == l']
-- for each cyclic edge with the right label,
-- add an edge from each of the new nodes (including this one)
++ [ (y,x,()) | (f,_,l') <- cyc, l == l', (y,_) <- newNodes]
newContexts = [ (x, l, to x l) | (x,l) <- newNodes ]
alphabet :: Eq b => Graph n a (Maybe b) -> [b]
alphabet = nub . catMaybes . map getLabel . edges
reachable :: (Eq b, Eq n) => Graph n a (Maybe b) -> n -> b -> [n]
reachable = undefined
determinize :: NFA a -> DFA a
determinize (FA g s f) = undefined
prFAGraphviz :: (Eq n,Show n) => FA n String String -> String
prFAGraphviz = Dot.prGraphviz . toGraphviz
toGraphviz :: (Eq n,Show n) => FA n String String -> Dot.Graph
toGraphviz (FA (Graph _ ns es) s f) = Dot.Graph Dot.Directed [] (map mkNode ns) (map mkEdge es)
where mkNode (n,l) = Dot.Node (show n) attrs
where attrs = [("label",l)]
++ if n == s then [("shape","box")] else []
++ if n `elem` f then [("style","bold")] else []
mkEdge (x,y,l) = Dot.Edge (show x) (show y) [("label",l)]
--
-- * Graphs
--
@@ -94,8 +129,6 @@ prFAGraphviz = Dot.prGraphviz . mkGraphviz
data Graph n a b = Graph [n] [(n,a)] [(n,n,b)]
deriving (Eq,Show)
type Node = Int
newGraph :: [n] -> Graph n a b
newGraph ns = Graph ns [] []
@@ -124,43 +157,9 @@ incoming (Graph _ ns es) = snd $ mapAccumL f (sortBy compareDest es) (sortBy com
compareFst p1 p2 = compare (fst p1) (fst p2)
f es' (n,l) = let (nes,es'') = span (destIs n) es' in (es'',(n,l,nes))
moveLabelsToNodes_ :: (Ord n, Eq a) => Graph n () (Maybe a) -> Graph n (Maybe a) ()
moveLabelsToNodes_ gr@(Graph c _ _) = mimimizeGr2 $ Graph c' (zip ns ls) (concat ess)
where is = incoming gr
(c',is') = mapAccumL fixIncoming c is
(ns,ls,ess) = unzip3 (concat is')
fixIncoming :: (Eq n, Eq a) => [n] -> (n,(),[(n,n,Maybe a)]) -> ([n],[(n,Maybe a,[(n,n,())])])
fixIncoming cs c@(n,(),es) = (cs'', (n,Nothing,es'):newContexts)
where ls = nub $ map getLabel es
(cs',cs'') = splitAt (length ls) cs
newNodes = zip cs' ls
es' = [ (x,n,()) | x <- map fst newNodes ]
-- separate cyclic and non-cyclic edges
(cyc,ncyc) = partition (\ (f,_,_) -> f == n) es
-- keep all incoming non-cyclic edges with the right label
to x l = [ (f,x,()) | (f,_,l') <- ncyc, l == l']
-- for each cyclic edge with the right label,
-- add an edge from each of the new nodes (including this one)
++ [ (y,x,()) | (f,_,l') <- cyc, l == l', (y,_) <- newNodes]
newContexts = [ (x, l, to x l) | (x,l) <- newNodes ]
getLabel :: (n,n,b) -> b
getLabel (_,_,l) = l
mimimizeGr1 :: Eq n => Graph n () (Maybe a) -> Graph n () (Maybe a)
mimimizeGr1 = removeEmptyLoops1
removeEmptyLoops1 :: Eq n => Graph n () (Maybe a) -> Graph n () (Maybe a)
removeEmptyLoops1 (Graph c ns es) = Graph c ns (filter (not . isEmptyLoop) es)
where isEmptyLoop (f,t,Nothing) | f == t = True
isEmptyLoop _ = False
mimimizeGr2 :: Graph n (Maybe a) () -> Graph n (Maybe a) ()
mimimizeGr2 = id
removeDuplicateEdges :: (Eq n, Ord b) => Graph n a b -> Graph n a b
removeDuplicateEdges (Graph c ns es) = Graph c ns (nub es)
reverseGraph :: Graph n a b -> Graph n a b
reverseGraph (Graph c ns es) = Graph c ns [ (t,f,l) | (f,t,l) <- es ]

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@@ -5,9 +5,9 @@
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/09/14 15:17:30 $
-- > CVS $Date: 2005/09/14 16:08:35 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.9 $
-- > CVS $Revision: 1.10 $
--
-- This module converts a CFG to an SLF finite-state network
-- for use with the ATK recognizer. The SLF format is described
@@ -71,7 +71,7 @@ regularPrinter = prCFRules . makeSimpleRegular
join g = concat . intersperse g
showRhs = unwords . map (symbol id show)
automatonToSLF :: FA (Maybe String) () -> SLF
automatonToSLF :: FA State (Maybe String) () -> SLF
automatonToSLF fa =
SLF { slfNodes = map mkSLFNode (states fa),
slfEdges = zipWith mkSLFEdge [0..] (transitions fa) }