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|
----------------------------------------------------------------------
-- |
-- Maintainer : Krasimir Angelov
-- Stability : (stable)
-- Portability : (portable)
--
-- MCFG parsing, the active algorithm
-----------------------------------------------------------------------------
module PGF.Parsing.FCFG.Active (parse) where
import GF.Data.Assoc
import GF.Data.SortedList
import GF.Data.Utilities
import qualified GF.Data.MultiMap as MM
import PGF.CId
import PGF.Data
import PGF.Parsing.FCFG.Utilities
import Control.Monad (guard)
import qualified Data.List as List
import qualified Data.Map as Map
import qualified Data.Set as Set
import Data.Array
----------------------------------------------------------------------
-- * parsing
makeFinalEdge cat 0 0 = (cat, [EmptyRange])
makeFinalEdge cat i j = (cat, [makeRange i j])
-- | the list of categories = possible starting categories
parse :: String -> ParserInfo -> CId -> [FToken] -> [Tree]
parse strategy pinfo start toks = nubsort $ filteredForests >>= forest2trees
where
inTokens = input toks
starts = Map.findWithDefault [] start (startupCats pinfo)
schart = xchart2syntaxchart chart pinfo
(i,j) = inputBounds inTokens
finalEdges = [makeFinalEdge cat i j | cat <- starts]
forests = chart2forests schart (const False) finalEdges
filteredForests = forests >>= applyProfileToForest
chart = process strategy pinfo inTokens axioms emptyXChart
axioms | isBU strategy = literals pinfo inTokens ++ initialBU pinfo inTokens
| isTD strategy = literals pinfo inTokens ++ initialTD pinfo starts inTokens
isBU s = s=="b"
isTD s = s=="t"
-- used in prediction
emptyChildren :: RuleId -> ParserInfo -> SyntaxNode RuleId RangeRec
emptyChildren ruleid pinfo = SNode ruleid (replicate (length rhs) [])
where
FRule _ _ rhs _ _ = allRules pinfo ! ruleid
process :: String -> ParserInfo -> Input FToken -> [(FCat,Item)] -> XChart FCat -> XChart FCat
process strategy pinfo toks [] chart = chart
process strategy pinfo toks ((c,item):items) chart = process strategy pinfo toks items $! univRule c item chart
where
univRule cat item@(Active found rng lbl ppos node@(SNode ruleid recs)) chart
| inRange (bounds lin) ppos =
case lin ! ppos of
FSymCat r d -> let c = args !! d
in case recs !! d of
[] -> case insertXChart chart item c of
Nothing -> chart
Just chart -> let items = do item@(Final found' _) <- lookupXChartFinal chart c
rng <- concatRange rng (found' !! r)
return (c, Active found rng lbl (ppos+1) (SNode ruleid (updateNth (const found') d recs)))
++
do guard (isTD strategy)
ruleid <- topdownRules pinfo ? c
return (c, Active [] EmptyRange 0 0 (emptyChildren ruleid pinfo))
in process strategy pinfo toks items chart
found' -> let items = do rng <- concatRange rng (found' !! r)
return (c, Active found rng lbl (ppos+1) node)
in process strategy pinfo toks items chart
FSymTok tok -> let items = do t_rng <- inputToken toks ? tok
rng' <- concatRange rng t_rng
return (cat, Active found rng' lbl (ppos+1) node)
in process strategy pinfo toks items chart
| otherwise =
if inRange (bounds lins) (lbl+1)
then univRule cat (Active (rng:found) EmptyRange (lbl+1) 0 node) chart
else univRule cat (Final (reverse (rng:found)) node) chart
where
(FRule _ _ args cat lins) = allRules pinfo ! ruleid
lin = lins ! lbl
univRule cat item@(Final found' node) chart =
case insertXChart chart item cat of
Nothing -> chart
Just chart -> let items = do (Active found rng l ppos node@(SNode ruleid _)) <- lookupXChartAct chart cat
let FRule _ _ args _ lins = allRules pinfo ! ruleid
FSymCat r d = lins ! l ! ppos
rng <- concatRange rng (found' !! r)
return (args !! d, Active found rng l (ppos+1) (updateChildren node d found'))
++
do guard (isBU strategy)
ruleid <- leftcornerCats pinfo ? cat
let FRule _ _ args _ lins = allRules pinfo ! ruleid
FSymCat r d = lins ! 0 ! 0
return (args !! d, Active [] (found' !! r) 0 1 (updateChildren (emptyChildren ruleid pinfo) d found'))
updateChildren :: SyntaxNode RuleId RangeRec -> Int -> RangeRec -> SyntaxNode RuleId RangeRec
updateChildren (SNode ruleid recs) i rec = SNode ruleid $! updateNth (const rec) i recs
in process strategy pinfo toks items chart
----------------------------------------------------------------------
-- * XChart
data Item
= Active RangeRec
Range
{-# UNPACK #-} !FIndex
{-# UNPACK #-} !FPointPos
(SyntaxNode RuleId RangeRec)
| Final RangeRec (SyntaxNode RuleId RangeRec)
deriving (Eq, Ord)
data XChart c = XChart !(MM.MultiMap c Item) !(MM.MultiMap c Item)
emptyXChart :: Ord c => XChart c
emptyXChart = XChart MM.empty MM.empty
insertXChart (XChart actives finals) item@(Active _ _ _ _ _) c =
case MM.insert' c item actives of
Nothing -> Nothing
Just actives -> Just (XChart actives finals)
insertXChart (XChart actives finals) item@(Final _ _) c =
case MM.insert' c item finals of
Nothing -> Nothing
Just finals -> Just (XChart actives finals)
lookupXChartAct (XChart actives finals) c = actives MM.! c
lookupXChartFinal (XChart actives finals) c = finals MM.! c
xchart2syntaxchart :: XChart FCat -> ParserInfo -> SyntaxChart (CId,[Profile]) (FCat,RangeRec)
xchart2syntaxchart (XChart actives finals) pinfo =
accumAssoc groupSyntaxNodes $
[ case node of
SNode ruleid rrecs -> let FRule fun prof rhs cat _ = allRules pinfo ! ruleid
in ((cat,found), SNode (fun,prof) (zip rhs rrecs))
SString s -> ((cat,found), SString s)
SInt n -> ((cat,found), SInt n)
SFloat f -> ((cat,found), SFloat f)
| (cat, Final found node) <- MM.toList finals
]
literals :: ParserInfo -> Input FToken -> [(FCat,Item)]
literals pinfo toks =
[let (c,node) = lexer t in (c,Final [rng] node) | (t,rngs) <- aAssocs (inputToken toks), rng <- rngs, not (t `elem` grammarToks pinfo)]
where
lexer t =
case reads t of
[(n,"")] -> (fcatInt, SInt (n::Integer))
_ -> case reads t of
[(f,"")] -> (fcatFloat, SFloat (f::Double))
_ -> (fcatString,SString t)
----------------------------------------------------------------------
-- Earley --
-- called with all starting categories
initialTD :: ParserInfo -> [FCat] -> Input FToken -> [(FCat,Item)]
initialTD pinfo starts toks =
do cat <- starts
ruleid <- topdownRules pinfo ? cat
return (cat,Active [] (Range 0 0) 0 0 (emptyChildren ruleid pinfo))
----------------------------------------------------------------------
-- Kilbury --
initialBU :: ParserInfo -> Input FToken -> [(FCat,Item)]
initialBU pinfo toks =
do (tok,rngs) <- aAssocs (inputToken toks)
ruleid <- leftcornerTokens pinfo ? tok
let FRule _ _ _ cat _ = allRules pinfo ! ruleid
rng <- rngs
return (cat,Active [] rng 0 1 (emptyChildren ruleid pinfo))
++
do ruleid <- epsilonRules pinfo
let FRule _ _ _ cat _ = allRules pinfo ! ruleid
return (cat,Active [] EmptyRange 0 0 (emptyChildren ruleid pinfo))
|
