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authorpeb <unknown>2005-03-21 21:31:43 +0000
committerpeb <unknown>2005-03-21 21:31:43 +0000
commit531be3a72e938f2360d312c7fd9cd173e5442594 (patch)
tree7857722b476b4091e600301525f394b98e886095 /src/GF/Parsing/CFParserGeneral.hs
parent75d228629a267da1be6c26a6fb13a14f3da0f7c2 (diff)
"Committed_by_peb"
Diffstat (limited to 'src/GF/Parsing/CFParserGeneral.hs')
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diff --git a/src/GF/Parsing/CFParserGeneral.hs b/src/GF/Parsing/CFParserGeneral.hs
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--- a/src/GF/Parsing/CFParserGeneral.hs
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@@ -1,85 +0,0 @@
-----------------------------------------------------------------------
--- |
--- Module : CFParserGeneral
--- Maintainer : Peter Ljunglöf
--- Stability : (stable)
--- Portability : (portable)
---
--- > CVS $Date: 2005/03/21 14:17:41 $
--- > CVS $Author: peb $
--- > CVS $Revision: 1.1 $
---
--- Several implementations of CFG chart parsing
------------------------------------------------------------------------------
-
-module GF.Parsing.CFParserGeneral (parse,
- Strategy
- ) where
-
-import Tracing
-
-import GF.Parsing.Parser
-import GF.Conversion.CFGrammar
-import GF.Parsing.GeneralChart
-import GF.Data.Assoc
-
-parse :: (Ord n, Ord c, Ord t) => Strategy -> CFParser n c t
-parse strategy grammar start = extract . process strategy grammar start
-
-type Strategy = (Bool, Bool) -- (isBottomup, isTopdown)
-
-extract :: [Item n (Symbol c t)] -> [Edge (Rule n c t)]
-extract edges =
- edges'
- where edges' = [ Edge j k (Rule cat (reverse found) name) |
- Edge j k (Cat cat, found, [], Just name) <- edges ]
-
-process :: (Ord n, Ord c, Ord t) => Strategy -> PInfo n c t ->
- [c] -> Input t -> [Item n (Symbol c t)]
-process (isBottomup, isTopdown) grammar start
- = trace ("CFParserGeneral" ++
- (if isBottomup then " BU" else "") ++
- (if isTopdown then " TD" else "")) $
- buildChart keyof [predict, combine] . axioms
- where axioms input = initial ++ scan input
-
- scan input = map (fmap mkEdge) (inputEdges input)
- mkEdge tok = (Tok tok, [], [], Nothing)
-
- -- the combine rule
- combine chart (Edge j k (next, _, [], _))
- = [ edge `forwardTo` k | edge <- chartLookup chart (Active next j) ]
- combine chart edge@(Edge _ j (_, _, next:_, _))
- = [ edge `forwardTo` k | Edge _ k _ <- chartLookup chart (Passive next j) ]
-
- -- initial predictions
- initial = [ loopingEdge 0 rule | cat <- start, rule <- tdRuleLookup ? cat ]
-
- -- predictions
- predict chart (Edge j k (next, _, [], _)) | isBottomup
- = [ loopingEdge j rule `forwardTo` k | rule <- bottomupRules grammar ? next ]
- -- - - - - - - - - - ^^^^^^^^^^^^^ Kilbury prediction: move dot forward
- predict chart (Edge _ k (_, _, Cat cat:_, _))
- = [ loopingEdge k rule | rule <- tdRuleLookup ? cat ]
- predict _ _ = []
-
- tdRuleLookup | isTopdown = topdownRules grammar
- | isBottomup = emptyLeftcornerRules grammar
-
--- internal representation of parse items
-
-type Item n s = Edge (s, [s], [s], Maybe n)
-type IChart n s = Chart (Item n s) (IKey s)
-data IKey s = Active s Int
- | Passive s Int
- deriving (Eq, Ord, Show)
-
-keyof (Edge _ j (_, _, next:_, _)) = Active next j
-keyof (Edge j _ (cat, _, [], _)) = Passive cat j
-
-forwardTo (Edge i j (cat, found, next:tofind, name)) k = Edge i k (cat, next:found, tofind, name)
-
-loopingEdge k (Rule cat tofind name) = Edge k k (Cat cat, [], tofind, Just name)
-
-
-