Files
gf-core/src/GF/Parsing/CFG.hs
2005-05-11 09:28:16 +00:00

52 lines
1.4 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/05/11 10:28:16 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.5 $
--
-- CFG parsing
-----------------------------------------------------------------------------
module GF.Parsing.CFG
(parseCF, module GF.Parsing.CFG.PInfo) where
import GF.Data.Operations (Err(..))
import GF.Formalism.Utilities
import GF.Formalism.CFG
import GF.Parsing.CFG.PInfo
import qualified GF.Parsing.CFG.Incremental as Inc
import qualified GF.Parsing.CFG.General as Gen
----------------------------------------------------------------------
-- parsing
parseCF :: (Ord n, Ord c, Ord t) => String -> Err (CFParser c n t)
parseCF "bottomup" = Ok $ Gen.parse bottomup
parseCF "topdown" = Ok $ Gen.parse topdown
parseCF "gb" = Ok $ Gen.parse bottomup
parseCF "gt" = Ok $ Gen.parse topdown
parseCF "ib" = Ok $ Inc.parse (bottomup, noFilter)
parseCF "it" = Ok $ Inc.parse (topdown, noFilter)
parseCF "ibFT" = Ok $ Inc.parse (bottomup, topdown)
parseCF "ibFB" = Ok $ Inc.parse (bottomup, bottomup)
parseCF "ibFTB" = Ok $ Inc.parse (bottomup, bothFilters)
parseCF "itF" = Ok $ Inc.parse (topdown, bottomup)
-- error parser:
parseCF prs = Bad $ "CFG parsing strategy not defined: " ++ prs
bottomup = (True, False)
topdown = (False, True)
noFilter = (False, False)
bothFilters = (True, True)