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Diffstat (limited to 'src-3.0/GF/Conversion/RemoveEpsilon.hs')
| -rw-r--r-- | src-3.0/GF/Conversion/RemoveEpsilon.hs | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/src-3.0/GF/Conversion/RemoveEpsilon.hs b/src-3.0/GF/Conversion/RemoveEpsilon.hs new file mode 100644 index 000000000..0e5dafb38 --- /dev/null +++ b/src-3.0/GF/Conversion/RemoveEpsilon.hs @@ -0,0 +1,46 @@ +---------------------------------------------------------------------- +-- | +-- Maintainer : PL +-- Stability : (stable) +-- Portability : (portable) +-- +-- > CVS $Date: 2005/05/30 08:11:32 $ +-- > CVS $Author: peb $ +-- > CVS $Revision: 1.3 $ +-- +-- Removing epsilon linearizations from MCF grammars +----------------------------------------------------------------------------- + + +module GF.Conversion.RemoveEpsilon where +-- (convertGrammar) where + +import GF.System.Tracing +import GF.Infra.Print + +import Control.Monad +import Data.List (mapAccumL) +import Data.Maybe (mapMaybe) +import GF.Formalism.Utilities +import GF.Formalism.GCFG +import GF.Formalism.MCFG +import GF.Conversion.Types +import GF.Data.Assoc +import GF.Data.SortedList +import GF.Data.GeneralDeduction + +convertGrammar :: EGrammar -> EGrammar +convertGrammar grammar = trace2 "RemoveEpsilon: initialEmpties" (prt initialEmpties) $ + trace2 "RemoveEpsilon: emptyCats" (prt emptyCats) $ + grammar + where initialEmpties = nubsort [ (cat, lbl) | + Rule (Abs cat _ _) (Cnc _ _ lins) <- grammar, + Lin lbl [] <- lins ] + emptyCats = limitEmpties initialEmpties + limitEmpties es = if es==es' then es else limitEmpties es' + where es' = nubsort [ (cat, lbl) | Rule (Abs cat _ _) (Cnc _ _ lins) <- grammar, + Lin lbl rhs <- lins, + all (symbol (\(c,l,n) -> (c,l) `elem` es) (const False)) rhs ] + + + |
