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|
----------------------------------------------------------------------
-- |
-- Maintainer : Krasimir Angelov
-- Stability : (stable)
-- Portability : (portable)
--
-- MCFG parsing, the active algorithm
-----------------------------------------------------------------------------
module GF.Parsing.FCFG.Active (parse) where
import GF.Data.GeneralDeduction
import GF.Data.Assoc
import GF.Data.SortedList
import GF.Data.Utilities
import GF.Formalism.FCFG
import GF.Formalism.Utilities
import GF.Infra.PrintClass
import GF.Parsing.FCFG.Range
import GF.Parsing.FCFG.PInfo
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
parse :: String -> FCFParser
parse strategy pinfo starts toks = xchart2syntaxchart chart pinfo
where chart = process strategy pinfo toks axioms emptyXChart
axioms | isBU strategy = literals pinfo toks ++ initialBU pinfo toks
| isTD strategy = literals pinfo toks ++ initialTD pinfo starts toks
isBU s = s=="b"
isTD s = s=="t"
-- used in prediction
emptyChildren :: RuleId -> FCFPInfo -> SyntaxNode RuleId RangeRec
emptyChildren ruleid pinfo = SNode ruleid (replicate (length rhs) [])
where
FRule _ rhs _ _ = allRules pinfo ! ruleid
process :: String -> FCFPInfo -> 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 c r d -> 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 (i,j) <- inputToken toks ? tok
rng' <- concatRange rng (makeRange i j)
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 fn _ 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 _ _ _ lins = allRules pinfo ! ruleid
FSymCat cat r d = lins ! l ! ppos
rng <- concatRange rng (found' !! r)
return (cat, Active found rng l (ppos+1) (updateChildren node d found'))
++
do guard (isBU strategy)
ruleid <- leftcornerCats pinfo ? cat
let FRule _ _ _ lins = allRules pinfo ! ruleid
FSymCat cat r d = lins ! 0 ! 0
return (cat, 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 !(ParseChart Item c) !(ParseChart Item c)
emptyXChart :: Ord c => XChart c
emptyXChart = XChart emptyChart emptyChart
insertXChart (XChart actives finals) item@(Active _ _ _ _ _) c =
case chartInsert actives item c of
Nothing -> Nothing
Just actives -> Just (XChart actives finals)
insertXChart (XChart actives finals) item@(Final _ _) c =
case chartInsert finals item c of
Nothing -> Nothing
Just finals -> Just (XChart actives finals)
lookupXChartAct (XChart actives finals) c = chartLookup actives c
lookupXChartFinal (XChart actives finals) c = chartLookup finals c
xchart2syntaxchart :: XChart FCat -> FCFPInfo -> SyntaxChart FName (FCat,RangeRec)
xchart2syntaxchart (XChart actives finals) pinfo =
accumAssoc groupSyntaxNodes $
[ case node of
SNode ruleid rrecs -> let FRule fun rhs cat _ = allRules pinfo ! ruleid
in ((cat,found), SNode fun (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) <- chartAssocs finals
]
literals :: FCFPInfo -> Input FToken -> [(FCat,Item)]
literals pinfo toks =
[let (c,node) = lexer t in (c,Final [makeRange i j] node) | Edge i j t <- inputEdges toks, 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 :: FCFPInfo -> [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 :: FCFPInfo -> Input FToken -> [(FCat,Item)]
initialBU pinfo toks =
do (tok,rngs) <- aAssocs (inputToken toks)
ruleid <- leftcornerTokens pinfo ? tok
let FRule _ _ cat _ = allRules pinfo ! ruleid
(i,j) <- rngs
return (cat,Active [] (makeRange i j) 0 1 (emptyChildren ruleid pinfo))
++
do ruleid <- epsilonRules pinfo
let FRule _ _ cat _ = allRules pinfo ! ruleid
return (cat,Active [] EmptyRange 0 0 (emptyChildren ruleid pinfo))
|
