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gf-core/src-3.0/GF/Parsing/MCFG/Range.hs

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Haskell

---------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/08/08 09:01:25 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.5 $
--
-- Definitions of ranges, and operations on ranges
-----------------------------------------------------------------------------
module GF.Parsing.MCFG.Range
( Range(..), makeRange, concatRange, rangeEdge, edgeRange, minRange, maxRange,
LinRec, RangeRec,
makeRangeRec, rangeRestRec, rangeRestrictRule,
projection, unifyRec, substArgRec
) where
-- Haskell
import Data.List
import Control.Monad
-- GF modules
import GF.Formalism.GCFG
import GF.Formalism.MCFG
import GF.Formalism.Utilities
import GF.Infra.Print
import GF.Data.Assoc ((?))
import GF.Data.Utilities (updateNthM)
------------------------------------------------------------
-- ranges as single pairs
data Range = Range (Int, Int)
| EmptyRange
deriving (Eq, Ord, Show)
makeRange :: (Int, Int) -> Range
concatRange :: Range -> Range -> [Range]
rangeEdge :: a -> Range -> Edge a
edgeRange :: Edge a -> Range
minRange :: Range -> Int
maxRange :: Range -> Int
makeRange = Range
concatRange EmptyRange rng = return rng
concatRange rng EmptyRange = return rng
concatRange (Range(i,j)) (Range(j',k)) = [ Range(i,k) | j==j']
rangeEdge a (Range(i,j)) = Edge i j a
edgeRange (Edge i j _) = Range (i,j)
minRange (Range rho) = fst rho
maxRange (Range rho) = snd rho
instance Print Range where
prt (Range (i,j)) = "(" ++ show i ++ "-" ++ show j ++ ")"
prt (EmptyRange) = "(?)"
{-- Types --------------------------------------------------------------------
Linearization- and Range records implemented as lists
-----------------------------------------------------------------------------}
type LinRec c l t = [Lin c l t]
type RangeRec l = [(l, Range)]
{-- Functions ----------------------------------------------------------------
Concatenation : Concatenation of Ranges, Symbols and Linearizations
and records of Linearizations
Record transformation : Makes a Range record from a fully instantiated
Linearization record
Record projection : Given a label, returns the corresponding Range
Range restriction : Range restriction of Tokens, Symbols,
Linearizations and Records given a list of Tokens
Record replacment : Substitute a record for another in a list of Range
records
Argument substitution : Substitution of a Cat c to a Tok Range, where
Range is the cover of c
Note: The argument is still a Symbol c Range
Subsumation : Checks if a Range record subsumes another Range
record
Record unification : Unification of two Range records
-----------------------------------------------------------------------------}
--- Concatenation ------------------------------------------------------------
concSymbols :: [Symbol c Range] -> [[Symbol c Range]]
concSymbols (Tok rng:Tok rng':toks) = do rng'' <- concatRange rng rng'
concSymbols (Tok rng'':toks)
concSymbols (sym:syms) = do syms' <- concSymbols syms
return (sym:syms')
concSymbols [] = return []
concLin :: Lin c l Range -> [Lin c l Range]
concLin (Lin lbl syms) = do syms' <- concSymbols syms
return (Lin lbl syms')
concLinRec :: LinRec c l Range -> [LinRec c l Range]
concLinRec = mapM concLin
--- Record transformation ----------------------------------------------------
makeRangeRec :: LinRec c l Range -> RangeRec l
makeRangeRec lins = map convLin lins
where convLin (Lin lbl [Tok rng]) = (lbl, rng)
convLin (Lin lbl []) = (lbl, EmptyRange)
convLin _ = error "makeRangeRec"
--- Record projection --------------------------------------------------------
projection :: Ord l => l -> RangeRec l -> [Range]
projection l rec = maybe (fail "projection") return $ lookup l rec
--- Range restriction --------------------------------------------------------
rangeRestTok :: Ord t => Input t -> t -> [Range]
rangeRestTok toks tok = do rng <- inputToken toks ? tok
return (makeRange rng)
rangeRestSym :: Ord t => Input t -> Symbol a t -> [Symbol a Range]
rangeRestSym toks (Tok tok) = do rng <- rangeRestTok toks tok
return (Tok rng)
rangeRestSym _ (Cat c) = return (Cat c)
rangeRestLin :: Ord t => Input t -> Lin c l t -> [Lin c l Range]
rangeRestLin toks (Lin lbl syms) = do syms' <- mapM (rangeRestSym toks) syms
concLin (Lin lbl syms')
-- return (Lin lbl syms')
rangeRestRec :: Ord t => Input t -> LinRec c l t -> [LinRec c l Range]
rangeRestRec toks = mapM (rangeRestLin toks)
rangeRestrictRule :: Ord t => Input t -> MCFRule c n l t -> [MCFRule c n l Range]
rangeRestrictRule toks (Rule abs (Cnc l ls lins)) = liftM (Rule abs . Cnc l ls) $
rangeRestRec toks lins
--- Argument substitution ----------------------------------------------------
substArgSymbol :: Ord l => Int -> RangeRec l -> Symbol (c, l, Int) Range
-> Symbol (c, l, Int) Range
substArgSymbol i rec tok@(Tok rng) = tok
substArgSymbol i rec cat@(Cat (c, l, j))
| i==j = maybe err Tok $ lookup l rec
| otherwise = cat
where err = error "substArg: Label not in range-record"
substArgLin :: Ord l => Int -> RangeRec l -> Lin c l Range
-> [Lin c l Range]
substArgLin i rec (Lin lbl syms) =
concLin (Lin lbl (map (substArgSymbol i rec) syms))
substArgRec :: Ord l => Int -> RangeRec l -> LinRec c l Range
-> [LinRec c l Range]
substArgRec i rec lins = mapM (substArgLin i rec) lins
-- Record unification & replacment ---------------------------------------------------------
unifyRec :: Ord l => [RangeRec l] -> Int -> RangeRec l -> [[RangeRec l]]
unifyRec recs i rec = updateNthM update i recs
where update rec' = guard (subsumes rec' rec) >> return rec
-- unifyRec recs i rec = do guard $ subsumes (recs !! i) rec
-- return $ replaceRec recs i rec
replaceRec :: [RangeRec l] -> Int -> RangeRec l -> [RangeRec l]
replaceRec recs i rec = before ++ (rec : after)
where (before, _ : after) = splitAt i recs
subsumes :: Ord l => RangeRec l -> RangeRec l -> Bool
subsumes rec rec' = and [r `elem` rec' | r <- rec]
-- subsumes rec rec' = all (`elem` rec') rec
{-
--- Record unification -------------------------------------------------------
unifyRangeRecs :: Ord l => [RangeRec l] -> [RangeRec l] -> [[RangeRec l]]
unifyRangeRecs recs recs' = zipWithM unify recs recs'
where unify :: Ord l => RangeRec l -> RangeRec l -> [RangeRec l]
unify rec [] = return rec
unify [] rec = return rec
unify rec1'@(p1@(l1, r1):rec1) rec2'@(p2@(l2, r2):rec2)
= case compare l1 l2 of
LT -> do rec3 <- unify rec1 rec2'
return (p1:rec3)
GT -> do rec3 <- unify rec1' rec2
return (p2:rec3)
EQ -> do guard (r1 == r2)
rec3 <- unify rec1 rec2
return (p1:rec3)
-}