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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.Tree
import PGF.Parsing.FCFG.Utilities
import PGF.BuildParser
import Control.Monad (guard)
import qualified Data.List as List
import qualified Data.Map as Map
import qualified Data.IntMap as IntMap
import qualified Data.Set as Set
import Data.Array.IArray
import Debug.Trace
----------------------------------------------------------------------
-- * parsing
type FToken = String
makeFinalEdge cat 0 0 = (cat, [EmptyRange])
makeFinalEdge cat i j = (cat, [makeRange i j])
-- | the list of categories = possible starting categories
parse :: String -> ParserInfo -> Type -> [FToken] -> [Expr]
parse strategy pinfo (DTyp _ start _) toks = map (tree2expr) . nubsort $ filteredForests >>= forest2trees
where
inTokens = input toks
starts = Map.findWithDefault [] start (startCats 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
pinfoex = buildParserInfo pinfo
chart = process strategy pinfo pinfoex inTokens axioms emptyXChart
axioms | isBU strategy = literals pinfoex inTokens ++ initialBU pinfo pinfoex inTokens
| isTD strategy = literals pinfoex inTokens ++ initialTD pinfo starts inTokens
isBU s = s=="b"
isTD s = s=="t"
-- used in prediction
emptyChildren :: FunId -> [FCat] -> SyntaxNode FunId RangeRec
emptyChildren ruleid args = SNode ruleid (replicate (length args) [])
process :: String -> ParserInfo -> ParserInfoEx -> Input FToken -> [Item] -> XChart FCat -> XChart FCat
process strategy pinfo pinfoex toks [] chart = chart
process strategy pinfo pinfoex toks (item:items) chart = process strategy pinfo pinfoex toks items $! univRule item chart
where
univRule item@(Active found rng lbl ppos node@(SNode ruleid recs) args cat) chart
| inRange (bounds lin) ppos =
case lin ! ppos of
FSymCat d r -> 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 (Active found rng lbl (ppos+1) (SNode ruleid (updateNth (const found') d recs)) args cat)
++
do guard (isTD strategy)
(ruleid,args) <- topdownRules pinfo c
return (Active [] EmptyRange 0 0 (emptyChildren ruleid args) args c)
in process strategy pinfo pinfoex toks items chart
found' -> let items = do rng <- concatRange rng (found' !! r)
return (Active found rng lbl (ppos+1) node args cat)
in process strategy pinfo pinfoex toks items chart
FSymKS [tok]
-> let items = do t_rng <- inputToken toks ? tok
rng' <- concatRange rng t_rng
return (Active found rng' lbl (ppos+1) node args cat)
in process strategy pinfo pinfoex toks items chart
| otherwise =
if inRange (bounds lins) (lbl+1)
then univRule (Active (rng:found) EmptyRange (lbl+1) 0 node args cat) chart
else univRule (Final (reverse (rng:found)) node args cat) chart
where
(FFun _ _ lins) = functions pinfo ! ruleid
lin = sequences pinfo ! (lins ! lbl)
univRule item@(Final found' node args cat) chart =
case insertXChart chart item cat of
Nothing -> chart
Just chart -> let items = do (Active found rng l ppos node@(SNode ruleid _) args c) <- lookupXChartAct chart cat
let FFun _ _ lins = functions pinfo ! ruleid
FSymCat d r = (sequences pinfo ! (lins ! l)) ! ppos
rng <- concatRange rng (found' !! r)
return (Active found rng l (ppos+1) (updateChildren node d found') args c)
++
do guard (isBU strategy)
(ruleid,args,c) <- leftcornerCats pinfoex ? cat
let FFun _ _ lins = functions pinfo ! ruleid
FSymCat d r = (sequences pinfo ! (lins ! 0)) ! 0
return (Active [] (found' !! r) 0 1 (updateChildren (emptyChildren ruleid args) d found') args c)
updateChildren :: SyntaxNode FunId RangeRec -> Int -> RangeRec -> SyntaxNode FunId RangeRec
updateChildren (SNode ruleid recs) i rec = SNode ruleid $! updateNth (const rec) i recs
in process strategy pinfo pinfoex toks items chart
----------------------------------------------------------------------
-- * XChart
data Item
= Active RangeRec
Range
{-# UNPACK #-} !FIndex
{-# UNPACK #-} !FPointPos
(SyntaxNode FunId RangeRec)
[FCat]
FCat
| Final RangeRec (SyntaxNode FunId RangeRec) [FCat] FCat
deriving (Eq, Ord, Show)
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 FFun fun prof _ = functions 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)
| (Final found node rhs cat) <- MM.elems finals
]
literals :: ParserInfoEx -> Input FToken -> [Item]
literals pinfoex toks =
[let (c,node) = lexer t in (Final [rng] node [] c) | (t,rngs) <- aAssocs (inputToken toks), rng <- rngs, not (t `elem` grammarToks pinfoex)]
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 -> [Item]
initialTD pinfo starts toks =
do cat <- starts
(ruleid,args) <- topdownRules pinfo cat
return (Active [] (Range 0 0) 0 0 (emptyChildren ruleid args) args cat)
topdownRules pinfo cat = f cat []
where
f cat rules = maybe rules (Set.fold g rules) (IntMap.lookup cat (productions pinfo))
g (FApply ruleid args) rules = (ruleid,args) : rules
g (FCoerce cat) rules = f cat rules
----------------------------------------------------------------------
-- Kilbury --
initialBU :: ParserInfo -> ParserInfoEx -> Input FToken -> [Item]
initialBU pinfo pinfoex toks =
do (tok,rngs) <- aAssocs (inputToken toks)
(ruleid,args,cat) <- leftcornerTokens pinfoex ? tok
rng <- rngs
return (Active [] rng 0 1 (emptyChildren ruleid args) args cat)
++
do (ruleid,args,cat) <- epsilonRules pinfoex
let FFun _ _ _ = functions pinfo ! ruleid
return (Active [] EmptyRange 0 0 (emptyChildren ruleid args) args cat)
|
