GF/src is now for 2.9, and the new sources are in src-3.0 - keep it this way until the release of GF 3

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 ]
+
+
+