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gf-core/src-3.0/GF/Parsing/MCFG/Active.hs

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Haskell

----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/08/08 09:01:25 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.5 $
--
-- MCFG parsing, the active algorithm
-----------------------------------------------------------------------------
module GF.Parsing.MCFG.Active (parse, parseR) where
import GF.Data.GeneralDeduction
import GF.Data.Assoc
import GF.Formalism.GCFG
import GF.Formalism.MCFG
import GF.Formalism.Utilities
import GF.Parsing.MCFG.Range
import GF.Parsing.MCFG.PInfo
import GF.System.Tracing
import Control.Monad (guard)
import GF.Infra.Print
----------------------------------------------------------------------
-- * parsing
parse :: (Ord n, Ord c, Ord l, Ord t) => String -> MCFParser c n l t
parse strategy pinfo starts toks =
accumAssoc groupSyntaxNodes $
[ ((cat, found), SNode fun (zip rhs rrecs)) |
Final (Abs cat rhs fun) found rrecs <- chartLookup chart Fin ]
where chart = process strategy pinfo starts toks
-- parseR :: (Ord n, Ord c, Ord l, Ord t) => String -> MCFParser c n l t
parseR strategy pinfo starts =
accumAssoc groupSyntaxNodes $
[ ((cat, found), SNode fun (zip rhs rrecs)) |
Final (Abs cat rhs fun) found rrecs <- chartLookup chart Fin ]
where chart = processR strategy pinfo starts
process :: (Ord n, Ord c, Ord l, Ord t) =>
String -> MCFPInfo c n l t -> [c] -> Input t -> AChart c n l
process strategy pinfo starts toks
= tracePrt "MCFG.Active - chart size" prtSizes $
buildChart keyof (complete : combine : convert : rules) axioms
where rules | isNil strategy = [scan]
| isBU strategy = [scan, predictKilbury pinfo toks]
| isTD strategy = [scan, predictEarley pinfo toks]
axioms | isNil strategy = predict pinfo toks
| isBU strategy = {- terminal pinfo toks ++ -} initialScan pinfo toks
| isTD strategy = initial pinfo starts toks
--processR :: (Ord n, Ord c, Ord l) =>
-- String -> MCFPInfo c n l Range -> [c] -> AChart c n l
processR strategy pinfo starts
= tracePrt "MCFG.Active Range - chart size" prtSizes $
-- tracePrt "MCFG.Active Range - final chart" prtChart $
buildChart keyof (complete : combine : convert : rules) axioms
where rules | isNil strategy = [scan]
| isBU strategy = [scan, predictKilburyR pinfo]
| isTD strategy = [scan, predictEarleyR pinfo]
axioms | isNil strategy = predictR pinfo
| isBU strategy = {- terminalR pinfo ++ -} initialScanR pinfo
| isTD strategy = initialR pinfo starts
isNil s = s=="n"
isBU s = s=="b"
isTD s = s=="t"
-- used in prediction
emptyChildren :: Abstract c n -> [RangeRec l]
emptyChildren (Abs _ rhs _) = replicate (length rhs) []
makeMaxRange (Range (_, j)) = Range (j, j)
makeMaxRange EmptyRange = EmptyRange
----------------------------------------------------------------------
-- * inference rules
-- completion
complete :: (Ord c, Ord n, Ord l) => AChart c n l -> Item c n l -> [Item c n l]
complete _ (Active rule found rng (Lin l []) (lin:lins) recs) =
return $ Active rule (found ++ [(l, rng)]) EmptyRange lin lins recs
complete _ _ = []
-- scanning
scan :: (Ord c, Ord n, Ord l) => AChart c n l -> Item c n l -> [Item c n l]
scan _ (Active rule found rng (Lin l (Tok rng':syms)) lins recs) =
do rng'' <- concatRange rng rng'
return $ Active rule found rng'' (Lin l syms) lins recs
scan _ _ = []
-- | Creates an Active Item every time it is possible to combine
-- an Active Item from the agenda with a Passive Item from the Chart
combine :: (Ord c, Ord n, Ord l) => AChart c n l -> Item c n l -> [Item c n l]
combine chart item@(Active _ _ _ (Lin _ (Cat (c,_,_):_)) _ _) =
do Passive _c found <- chartLookup chart (Pass c)
combine2 chart found item
combine chart (Passive c found) =
do item <- chartLookup chart (Act c)
combine2 chart found item
combine _ _ = []
combine2 chart found' (Active rule found rng (Lin l (Cat (c, r, d):syms)) lins recs) =
do rng' <- projection r found'
rng'' <- concatRange rng rng'
recs' <- unifyRec recs d found'
return $ Active rule found rng'' (Lin l syms) lins recs'
-- | Active Items with nothing to find are converted to Final items,
-- which in turn are converted to Passive Items
convert :: (Ord c, Ord n, Ord l) => AChart c n l -> Item c n l -> [Item c n l]
convert _ (Active rule found rng (Lin lbl []) [] recs) =
return $ Final rule (found ++ [(lbl,rng)]) recs
convert _ (Final (Abs cat _ _) found _) =
return $ Passive cat found
convert _ _ = []
----------------------------------------------------------------------
-- Naive --
predict :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> Input t -> [Item c n l]
predict pinfo toks = tracePrt "MCFG.Active (Naive) - predicted rules" (prt . length) $
do (Rule abs (Cnc _ _ lins)) <- rulesMatchingInput pinfo toks
(lin':lins') <- rangeRestRec toks lins
return $ Active abs [] EmptyRange lin' lins' (emptyChildren abs)
----------------------------------------------------------------------
-- NaiveR --
predictR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range -> [Item c n l]
predictR pinfo = tracePrt "MCFG.Active (Naive Range) - predicted rules" (prt . length) $
do (Rule abs (Cnc _ _ (lin:lins))) <- allRules pinfo
return $ Active abs [] EmptyRange lin lins (emptyChildren abs)
----------------------------------------------------------------------
-- Earley --
-- anropas med alla startkategorier
initial :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> [c] -> Input t -> [Item c n l]
initial pinfo starts toks =
tracePrt "MCFG.Active (Earley) - initial rules" (prt . length) $
do cat <- starts
Rule abs (Cnc _ _ lins) <- topdownRules pinfo ? cat
lin' : lins' <- rangeRestRec toks lins
return $ Active abs [] (Range (0, 0)) lin' lins' (emptyChildren abs)
predictEarley :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> Input t
-> AChart c n l -> Item c n l -> [Item c n l]
predictEarley pinfo toks _ item@(Active (Abs _ _ f) _ rng (Lin _ (Cat (cat,_,_):_)) _ _) =
topdownRules pinfo ? cat >>= predictEarley2 toks rng
predictEarley _ _ _ _ = []
predictEarley2 :: (Ord c, Ord n, Ord l, Ord t) => Input t -> Range -> MCFRule c n l t -> [Item c n l]
predictEarley2 toks _ (Rule abs@(Abs _ [] _) (Cnc _ _ lins)) =
do lins' <- rangeRestRec toks lins
return $ Final abs (makeRangeRec lins') []
predictEarley2 toks rng (Rule abs (Cnc _ _ lins)) =
do lin' : lins' <- rangeRestRec toks lins
return $ Active abs [] EmptyRange lin' lins' (emptyChildren abs)
----------------------------------------------------------------------
-- Earley Range --
initialR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range -> [c] -> [Item c n l]
initialR pinfo starts =
tracePrt "MCFG.Active (Earley Range) - initial rules" (prt . length) $
do cat <- starts
Rule abs (Cnc _ _ (lin : lins)) <- topdownRules pinfo ? cat
return $ Active abs [] (Range (0, 0)) lin lins (emptyChildren abs)
predictEarleyR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range
-> AChart c n l -> Item c n l -> [Item c n l]
predictEarleyR pinfo _ item@(Active (Abs _ _ f) _ rng (Lin _ (Cat (cat,_,_):_)) _ _) =
topdownRules pinfo ? cat >>= predictEarleyR2 rng
predictEarleyR _ _ _ = []
predictEarleyR2 :: (Ord c, Ord n, Ord l) => Range -> MCFRule c n l Range -> [Item c n l]
predictEarleyR2 _ (Rule abs@(Abs _ [] _) (Cnc _ _ lins)) =
return $ Final abs (makeRangeRec lins) []
predictEarleyR2 rng (Rule abs (Cnc _ _ (lin : lins))) =
return $ Active abs [] EmptyRange lin lins (emptyChildren abs)
----------------------------------------------------------------------
-- Kilbury --
-- terminal :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> Input t -> [Item c n l]
-- terminal pinfo toks =
-- tracePrt "MCFG.Active (Kilbury) - initial terminal rules" (prt . length) $
-- do Rule abs (Cnc _ _ lins) <- emptyRules pinfo
-- lins' <- rangeRestRec toks lins
-- return $ Final abs (makeRangeRec lins') []
initialScan :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> Input t -> [Item c n l]
initialScan pinfo toks =
tracePrt "MCFG.Active (Kilbury) - initial scanned rules + epsilon rules" (prt . length) $
do tok <- aElems (inputToken toks)
Rule abs (Cnc _ _ lins) <-
leftcornerTokens pinfo ? tok ++
epsilonRules pinfo
lin' : lins' <- rangeRestRec toks lins
return $ Active abs [] EmptyRange lin' lins' (emptyChildren abs)
predictKilbury :: (Ord c, Ord n, Ord l, Ord t) => MCFPInfo c n l t -> Input t
-> AChart c n l -> Item c n l -> [Item c n l]
predictKilbury pinfo toks _ (Passive cat found) =
do Rule abs (Cnc _ _ (Lin l (Cat (_,r,i):syms) : lins)) <- leftcornerCats pinfo ? cat
lin' : lins' <- rangeRestRec toks (Lin l syms : lins)
rng <- projection r found
children <- unifyRec (emptyChildren abs) i found
return $ Active abs [] rng lin' lins' children
predictKilbury _ _ _ _ = []
----------------------------------------------------------------------
-- KilburyR --
-- terminalR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range -> [Item c n l]
-- terminalR pinfo =
-- tracePrt "MCFG.Active (Kilbury Range) - initial terminal rules" (prt . length) $
-- do Rule abs (Cnc _ _ lins) <- emptyRules pinfo
-- return $ Final abs (makeRangeRec lins) []
initialScanR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range -> [Item c n l]
initialScanR pinfo =
tracePrt "MCFG.Active (Kilbury Range) - initial scanned rules" (prt . length) $
do Rule abs (Cnc _ _ (lin : lins)) <-
concatMap snd (aAssocs (leftcornerTokens pinfo)) ++
epsilonRules pinfo
return $ Active abs [] EmptyRange lin lins (emptyChildren abs)
predictKilburyR :: (Ord c, Ord n, Ord l) => MCFPInfo c n l Range
-> AChart c n l -> Item c n l -> [Item c n l]
predictKilburyR pinfo _ (Passive cat found) =
do Rule abs (Cnc _ _ (Lin l (Cat (_,r,i):syms) : lins)) <- leftcornerCats pinfo ? cat
rng <- projection r found
children <- unifyRec (emptyChildren abs) i found
return $ Active abs [] rng (Lin l syms) lins children
predictKilburyR _ _ _ = []
----------------------------------------------------------------------
-- * type definitions
type AChart c n l = ParseChart (Item c n l) (AKey c)
data Item c n l = Active (Abstract c n)
(RangeRec l)
Range
(Lin c l Range)
(LinRec c l Range)
[RangeRec l]
| Final (Abstract c n) (RangeRec l) [RangeRec l]
| Passive c (RangeRec l)
deriving (Eq, Ord, Show)
data AKey c = Act c
| Pass c
| Useless
| Fin
deriving (Eq, Ord, Show)
keyof :: Item c n l -> AKey c
keyof (Active _ _ _ (Lin _ (Cat (next, _, _):_)) _ _) = Act next
keyof (Final _ _ _) = Fin
keyof (Passive cat _) = Pass cat
keyof _ = Useless
----------------------------------------------------------------------
-- for tracing purposes
prtSizes chart = "final=" ++ show (length (chartLookup chart Fin)) ++
", passive=" ++ show (sum [length (chartLookup chart k) |
k@(Pass _) <- chartKeys chart ]) ++
", active=" ++ show (sum [length (chartLookup chart k) |
k@(Act _) <- chartKeys chart ]) ++
", useless=" ++ show (length (chartLookup chart Useless))
prtChart chart = concat [ "\n*** KEY: " ++ prt k ++
prtBefore "\n " (chartLookup chart k) |
k <- chartKeys chart ]
prtFinals chart = prtBefore "\n " (chartLookup chart Fin)
instance (Print c, Print n, Print l) => Print (Item c n l) where
prt (Active abs found rng lin tofind children) =
"? " ++ prt abs ++ ";\n\t" ++
"{" ++ prtSep " " found ++ "} " ++ prt rng ++ " . " ++
prt lin ++ " {" ++ prtSep " " tofind ++ "}" ++
( if null children then ";" else ";\n\t" ++
"{" ++ prtSep "} {" (map (prtSep " ") children) ++ "}" )
prt (Passive c rrec) = "- " ++ prt c ++ "; {" ++ prtSep " " rrec ++ "}"
prt (Final abs rr rrs) = ": " ++ prt abs ++ ";\n\t{" ++ prtSep " " rr ++ "}" ++
( if null rrs then ";" else ";\n\t" ++
"{" ++ prtSep "} {" (map (prtSep " ") rrs) ++ "}" )
instance Print c => Print (AKey c) where
prt (Act c) = "Active " ++ prt c
prt (Pass c) = "Passive " ++ prt c
prt (Fin) = "Final"
prt (Useless) = "Useless"