Files
gf-core/src/GF/OldParsing/ConvertSimpleToMCFG/Coercions.hs
2005-04-11 12:57:45 +00:00

71 lines
2.2 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/11 13:52:56 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.1 $
--
-- Adding coercion functions to a MCFG if necessary.
-----------------------------------------------------------------------------
module GF.OldParsing.ConvertSimpleToMCFG.Coercions (addCoercions) where
import GF.System.Tracing
import GF.Printing.PrintParser
import GF.Printing.PrintSimplifiedTerm
-- import PrintGFC
-- import qualified PrGrammar as PG
import qualified Ident
import GF.OldParsing.Utilities
--import GF.OldParsing.GrammarTypes
import GF.OldParsing.MCFGrammar (Rule(..), Lin(..))
import GF.Data.SortedList
import List (groupBy) -- , transpose)
----------------------------------------------------------------------
--addCoercions :: MCFGrammar -> MCFGrammar
addCoercions rules = coercions ++ rules
where (allHeads, allArgs) = unzip [ ((head, lbls), nubsort args) |
Rule head args lins _ <- rules,
let lbls = [ lbl | Lin lbl _ <- lins ] ]
allHeadSet = nubsort allHeads
allArgSet = union allArgs <\\> map fst allHeadSet
coercions = tracePrt "#coercions total" (prt . length) $
concat $
tracePrt "#coercions per cat" (prtList . map length) $
combineCoercions
(groupBy sameCatFst allHeadSet)
(groupBy sameCat allArgSet)
sameCatFst a b = sameCat (fst a) (fst b)
combineCoercions [] _ = []
combineCoercions _ [] = []
combineCoercions allHeads'@(heads:allHeads) allArgs'@(args:allArgs)
= case compare (mainCat $ fst $ head heads) (mainCat $ head args) of
LT -> combineCoercions allHeads allArgs'
GT -> combineCoercions allHeads' allArgs
EQ -> makeCoercion heads args : combineCoercions allHeads allArgs
makeCoercion heads args = [ Rule arg [head] lins coercionName |
(head@({-MCFCat-}(_, headCns), lbls) <- heads,
let lins = [ Lin lbl [Cat (head, lbl, 0)] | lbl <- lbls ],
arg@({-MCFCat-} (_, argCns) <- args,
argCns `subset` headCns ]
coercionName = Ident.IW
mainCat ({-MCFCat-} (c, _) = c
sameCat mc1 mc2 = mainCat mc1 == mainCat mc2