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gf-core/src/PGF/Parsing/FCFG/Incremental.hs
krasimir b8df9c92bb fix typo
2009-10-23 12:16:29 +00:00

372 lines
17 KiB
Haskell

{-# LANGUAGE BangPatterns #-}
module PGF.Parsing.FCFG.Incremental
( ParseState
, ErrorState
, initState
, nextState
, getCompletions
, recoveryStates
, extractTrees
, parse
, parseWithRecovery
) where
import Data.Array.IArray
import Data.Array.Base (unsafeAt)
import Data.List (isPrefixOf, foldl')
import Data.Maybe (fromMaybe, maybe)
import qualified Data.Map as Map
import qualified GF.Data.TrieMap as TMap
import qualified Data.IntMap as IntMap
import qualified Data.Set as Set
import Control.Monad
import GF.Data.SortedList
import PGF.CId
import PGF.Data
import PGF.Expr(Tree)
import PGF.Macros
import PGF.TypeCheck
import Debug.Trace
parse :: PGF -> Language -> Type -> [String] -> [Tree]
parse pgf lang typ toks = loop (initState pgf lang typ) toks
where
loop ps [] = extractTrees ps typ
loop ps (t:ts) = case nextState ps t of
Left es -> []
Right ps -> loop ps ts
parseWithRecovery :: PGF -> Language -> Type -> [Type] -> [String] -> [Tree]
parseWithRecovery pgf lang typ open_typs toks = accept (initState pgf lang typ) toks
where
accept ps [] = extractTrees ps typ
accept ps (t:ts) =
case nextState ps t of
Right ps -> accept ps ts
Left es -> skip (recoveryStates open_typs es) ts
skip ps_map [] = extractTrees (fst ps_map) typ
skip ps_map (t:ts) =
case Map.lookup t (snd ps_map) of
Just ps -> accept ps ts
Nothing -> skip ps_map ts
-- | Creates an initial parsing state for a given language and
-- startup category.
initState :: PGF -> Language -> Type -> ParseState
initState pgf lang (DTyp _ start _) =
let items = do
cat <- fromMaybe [] (Map.lookup start (startCats pinfo))
(funid,args) <- foldForest (\funid args -> (:) (funid,args)) (\_ _ args -> args)
[] cat (productions pinfo)
let FFun fn _ lins = functions pinfo ! funid
(lbl,seqid) <- assocs lins
return (Active 0 0 funid seqid args (AK cat lbl))
pinfo =
case lookParser pgf lang of
Just pinfo -> pinfo
_ -> error ("Unknown language: " ++ showCId lang)
in PState pgf
pinfo
(Chart emptyAC [] emptyPC (productions pinfo) (totalCats pinfo) 0)
(TMap.singleton [] (Set.fromList items))
-- | From the current state and the next token
-- 'nextState' computes a new state, where the token
-- is consumed and the current position is shifted by one.
-- If the new token cannot be accepted then an error state
-- is returned.
nextState :: ParseState -> String -> Either ErrorState ParseState
nextState (PState pgf pinfo chart items) t =
let (mb_agenda,map_items) = TMap.decompose items
agenda = maybe [] Set.toList mb_agenda
acc = fromMaybe TMap.empty (Map.lookup t map_items)
(acc1,chart1) = process (Just t) add (sequences pinfo) (functions pinfo) agenda acc chart
chart2 = chart1{ active =emptyAC
, actives=active chart1 : actives chart1
, passive=emptyPC
, offset =offset chart1+1
}
in if TMap.null acc1
then Left (EState pgf pinfo chart2)
else Right (PState pgf pinfo chart2 acc1)
where
add (tok:toks) item acc
| tok == t = TMap.insertWith Set.union toks (Set.singleton item) acc
add _ item acc = acc
-- | If the next token is not known but only its prefix (possible empty prefix)
-- then the 'getCompletions' function can be used to calculate the possible
-- next words and the consequent states. This is used for word completions in
-- the GF interpreter.
getCompletions :: ParseState -> String -> Map.Map String ParseState
getCompletions (PState pgf pinfo chart items) w =
let (mb_agenda,map_items) = TMap.decompose items
agenda = maybe [] Set.toList mb_agenda
acc = Map.filterWithKey (\tok _ -> isPrefixOf w tok) map_items
(acc',chart1) = process Nothing add (sequences pinfo) (functions pinfo) agenda acc chart
chart2 = chart1{ active =emptyAC
, actives=active chart1 : actives chart1
, passive=emptyPC
, offset =offset chart1+1
}
in fmap (PState pgf pinfo chart2) acc'
where
add (tok:toks) item acc
| isPrefixOf w tok = Map.insertWith (TMap.unionWith Set.union) tok (TMap.singleton toks (Set.singleton item)) acc
add _ item acc = acc
recoveryStates :: [Type] -> ErrorState -> (ParseState, Map.Map String ParseState)
recoveryStates open_types (EState pgf pinfo chart) =
let open_fcats = concatMap type2fcats open_types
agenda = foldl (complete open_fcats) [] (actives chart)
(acc,chart1) = process Nothing add (sequences pinfo) (functions pinfo) agenda Map.empty chart
chart2 = chart1{ active =emptyAC
, actives=active chart1 : actives chart1
, passive=emptyPC
, offset =offset chart1+1
}
in (PState pgf pinfo chart (TMap.singleton [] (Set.fromList agenda)), fmap (PState pgf pinfo chart2) acc)
where
type2fcats (DTyp _ cat _) = fromMaybe [] (Map.lookup cat (startCats pinfo))
complete open_fcats items ac =
foldl (Set.fold (\(Active j' ppos funid seqid args keyc) ->
(:) (Active j' (ppos+1) funid seqid args keyc)))
items
[set | fcat <- open_fcats, set <- lookupACByFCat fcat ac]
add (tok:toks) item acc = Map.insertWith (TMap.unionWith Set.union) tok (TMap.singleton toks (Set.singleton item)) acc
-- | This function extracts the list of all completed parse trees
-- that spans the whole input consumed so far. The trees are also
-- limited by the category specified, which is usually
-- the same as the startup category.
extractTrees :: ParseState -> Type -> [Tree]
extractTrees (PState pgf pinfo chart items) ty@(DTyp _ start _) =
nubsort [e1 | e <- exps, Right e1 <- [checkExpr pgf e ty]]
where
(mb_agenda,acc) = TMap.decompose items
agenda = maybe [] Set.toList mb_agenda
(_,st) = process Nothing (\_ _ -> id) (sequences pinfo) (functions pinfo) agenda () chart
exps = do
cat <- fromMaybe [] (Map.lookup start (startCats pinfo))
(funid,args) <- foldForest (\funid args -> (:) (funid,args)) (\_ _ args -> args)
[] cat (productions pinfo)
let FFun fn _ lins = functions pinfo ! funid
lbl <- indices lins
Just fid <- [lookupPC (PK cat lbl 0) (passive st)]
(fvs,tree) <- go Set.empty 0 (0,fid)
guard (Set.null fvs)
return tree
go rec fcat' (d,fcat)
| fcat < totalCats pinfo = return (Set.empty,EMeta (fcat'*10+d)) -- FIXME: here we assume that every rule has at most 10 arguments
| Set.member fcat rec = mzero
| otherwise = foldForest (\funid args trees ->
do let FFun fn _ lins = functions pinfo ! funid
args <- mapM (go (Set.insert fcat rec) fcat) (zip [0..] args)
check_ho_fun fn args
`mplus`
trees)
(\const _ trees ->
return (freeVar const,const)
`mplus`
trees)
[] fcat (forest st)
check_ho_fun fun args
| fun == _V = return (head args)
| fun == _B = return (foldl1 Set.difference (map fst args), foldr (\x e -> EAbs Explicit (mkVar (snd x)) e) (snd (head args)) (tail args))
| otherwise = return (Set.unions (map fst args),foldl (\e x -> EApp e (snd x)) (EFun fun) args)
mkVar (EFun v) = v
mkVar (EMeta _) = wildCId
freeVar (EFun v) = Set.singleton v
freeVar _ = Set.empty
_B = mkCId "_B"
_V = mkCId "_V"
process mbt fn !seqs !funs [] acc chart = (acc,chart)
process mbt fn !seqs !funs (item@(Active j ppos funid seqid args key0):items) acc chart
| inRange (bounds lin) ppos =
case unsafeAt lin ppos of
FSymCat d r -> let !fid = args !! d
key = AK fid r
items2 = case lookupPC (mkPK key k) (passive chart) of
Nothing -> items
Just id -> (Active j (ppos+1) funid seqid (updateAt d id args) key0) : items
items3 = foldForest (\funid args items -> Active k 0 funid (rhs funid r) args key : items)
(\_ _ items -> items)
items2 fid (forest chart)
in case lookupAC key (active chart) of
Nothing -> process mbt fn seqs funs items3 acc chart{active=insertAC key (Set.singleton item) (active chart)}
Just set | Set.member item set -> process mbt fn seqs funs items acc chart
| otherwise -> process mbt fn seqs funs items2 acc chart{active=insertAC key (Set.insert item set) (active chart)}
FSymKS toks -> let !acc' = fn toks (Active j (ppos+1) funid seqid args key0) acc
in process mbt fn seqs funs items acc' chart
FSymKP strs vars
-> let !acc' = foldl (\acc toks -> fn toks (Active j (ppos+1) funid seqid args key0) acc) acc
(strs:[strs' | Alt strs' _ <- vars])
in process mbt fn seqs funs items acc' chart
FSymLit d r -> let !fid = args !! d
in case [ts | FConst _ ts <- maybe [] Set.toList (IntMap.lookup fid (forest chart))] of
(toks:_) -> let !acc' = fn toks (Active j (ppos+1) funid seqid args key0) acc
in process mbt fn seqs funs items acc' chart
[] -> case litCatMatch fid mbt of
Just (toks,lit) -> let fid' = nextId chart
!acc' = fn toks (Active j (ppos+1) funid seqid (updateAt d fid' args) key0) acc
in process mbt fn seqs funs items acc' chart{forest=IntMap.insert fid' (Set.singleton (FConst lit toks)) (forest chart)
,nextId=nextId chart+1
}
Nothing -> process mbt fn seqs funs items acc chart
| otherwise =
case lookupPC (mkPK key0 j) (passive chart) of
Nothing -> let fid = nextId chart
items2 = case lookupAC key0 ((active chart:actives chart) !! (k-j)) of
Nothing -> items
Just set -> Set.fold (\(Active j' ppos funid seqid args keyc) ->
let FSymCat d _ = unsafeAt (unsafeAt seqs seqid) ppos
in (:) (Active j' (ppos+1) funid seqid (updateAt d fid args) keyc)) items set
in process mbt fn seqs funs items2 acc chart{passive=insertPC (mkPK key0 j) fid (passive chart)
,forest =IntMap.insert fid (Set.singleton (FApply funid args)) (forest chart)
,nextId =nextId chart+1
}
Just id -> let items2 = [Active k 0 funid (rhs funid r) args (AK id r) | r <- labelsAC id (active chart)] ++ items
in process mbt fn seqs funs items2 acc chart{forest = IntMap.insertWith Set.union id (Set.singleton (FApply funid args)) (forest chart)}
where
!lin = unsafeAt seqs seqid
!k = offset chart
mkPK (AK fid lbl) j = PK fid lbl j
rhs funid lbl = unsafeAt lins lbl
where
FFun _ _ lins = unsafeAt funs funid
updateAt :: Int -> a -> [a] -> [a]
updateAt nr x xs = [if i == nr then x else y | (i,y) <- zip [0..] xs]
litCatMatch fcat (Just t)
| fcat == fcatString = Just ([t],ELit (LStr t))
| fcat == fcatInt = case reads t of {[(n,"")] -> Just ([t],ELit (LInt n));
_ -> Nothing }
| fcat == fcatFloat = case reads t of {[(d,"")] -> Just ([t],ELit (LFlt d));
_ -> Nothing }
| fcat == fcatVar = Just ([t],EFun (mkCId t))
litCatMatch _ _ = Nothing
----------------------------------------------------------------
-- Active Chart
----------------------------------------------------------------
data Active
= Active {-# UNPACK #-} !Int
{-# UNPACK #-} !FPointPos
{-# UNPACK #-} !FunId
{-# UNPACK #-} !SeqId
[FCat]
{-# UNPACK #-} !ActiveKey
deriving (Eq,Show,Ord)
data ActiveKey
= AK {-# UNPACK #-} !FCat
{-# UNPACK #-} !FIndex
deriving (Eq,Ord,Show)
type ActiveChart = IntMap.IntMap (IntMap.IntMap (Set.Set Active))
emptyAC :: ActiveChart
emptyAC = IntMap.empty
lookupAC :: ActiveKey -> ActiveChart -> Maybe (Set.Set Active)
lookupAC (AK fcat l) chart = IntMap.lookup fcat chart >>= IntMap.lookup l
lookupACByFCat :: FCat -> ActiveChart -> [Set.Set Active]
lookupACByFCat fcat chart =
case IntMap.lookup fcat chart of
Nothing -> []
Just map -> IntMap.elems map
labelsAC :: FCat -> ActiveChart -> [FIndex]
labelsAC fcat chart =
case IntMap.lookup fcat chart of
Nothing -> []
Just map -> IntMap.keys map
insertAC :: ActiveKey -> Set.Set Active -> ActiveChart -> ActiveChart
insertAC (AK fcat l) set chart = IntMap.insertWith IntMap.union fcat (IntMap.singleton l set) chart
----------------------------------------------------------------
-- Passive Chart
----------------------------------------------------------------
data PassiveKey
= PK {-# UNPACK #-} !FCat
{-# UNPACK #-} !FIndex
{-# UNPACK #-} !Int
deriving (Eq,Ord,Show)
type PassiveChart = Map.Map PassiveKey FCat
emptyPC :: PassiveChart
emptyPC = Map.empty
lookupPC :: PassiveKey -> PassiveChart -> Maybe FCat
lookupPC key chart = Map.lookup key chart
insertPC :: PassiveKey -> FCat -> PassiveChart -> PassiveChart
insertPC key fcat chart = Map.insert key fcat chart
----------------------------------------------------------------
-- Forest
----------------------------------------------------------------
foldForest :: (FunId -> [FCat] -> b -> b) -> (Expr -> [String] -> b -> b) -> b -> FCat -> IntMap.IntMap (Set.Set Production) -> b
foldForest f g b fcat forest =
case IntMap.lookup fcat forest of
Nothing -> b
Just set -> Set.fold foldProd b set
where
foldProd (FCoerce fcat) b = foldForest f g b fcat forest
foldProd (FApply funid args) b = f funid args b
foldProd (FConst const toks) b = g const toks b
----------------------------------------------------------------
-- Parse State
----------------------------------------------------------------
-- | An abstract data type whose values represent
-- the current state in an incremental parser.
data ParseState = PState PGF ParserInfo Chart (TMap.TrieMap String (Set.Set Active))
data Chart
= Chart
{ active :: ActiveChart
, actives :: [ActiveChart]
, passive :: PassiveChart
, forest :: IntMap.IntMap (Set.Set Production)
, nextId :: {-# UNPACK #-} !FCat
, offset :: {-# UNPACK #-} !Int
}
deriving Show
----------------------------------------------------------------
-- Error State
----------------------------------------------------------------
-- | An abstract data type whose values represent
-- the state in an incremental parser after an error.
data ErrorState = EState PGF ParserInfo Chart