"Committed_by_peb"

src/GF/OldParsing/GeneralChart.hs

@@ -0,0 +1,86 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : GeneralChart
+-- Maintainer  : Peter Ljunglöf
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/04/11 13:52:53 $ 
+-- > CVS $Author: peb $
+-- > CVS $Revision: 1.1 $
+--
+-- Simple implementation of deductive chart parsing
+-----------------------------------------------------------------------------
+
+
+module GF.OldParsing.GeneralChart
+    (-- * Type definition
+     Chart,
+     -- * Main functions
+     chartLookup,
+     buildChart,
+     -- * Probably not needed
+     emptyChart,
+     chartMember,
+     chartInsert,
+     chartList,
+     addToChart
+    ) where
+
+-- import Trace 
+
+import GF.Data.RedBlackSet
+
+-- main functions
+
+chartLookup :: (Ord item, Ord key) => Chart item key -> key -> [item]
+buildChart  :: (Ord item, Ord key) => (item -> key) -> 
+	       [Chart item key -> item -> [item]] -> [item] -> [item]
+
+buildChart keyof rules axioms     = chartList (addItems axioms emptyChart)
+    where addItems []             = id
+	  addItems (item:items)   = addItems items . addItem item
+
+          -- addItem item | trace ("+ "++show item++"\n") False = undefined
+          addItem item            = addToChart item (keyof item) 
+				    (\chart -> foldr (consequence item) chart rules)
+
+          consequence item rule chart = addItems (rule chart item) chart
+
+-- probably not needed
+
+emptyChart  :: (Ord item, Ord key) => Chart item key
+chartMember :: (Ord item, Ord key) => Chart item key -> item -> key -> Bool
+chartInsert :: (Ord item, Ord key) => Chart item key -> item -> key -> Maybe (Chart item key)
+chartList   :: (Ord item, Ord key) => Chart item key -> [item]
+addToChart  :: (Ord item, Ord key) => item -> key -> (Chart item key -> Chart item key) -> Chart item key -> Chart item key
+
+addToChart item key after chart = maybe chart after (chartInsert chart item key)
+
+
+--------------------------------------------------------------------------------
+-- key charts as red/black trees
+
+newtype Chart         item key = KC (RedBlackMap key item)
+    deriving Show
+
+emptyChart                     = KC rbmEmpty
+chartMember (KC tree) item key = rbmElem key item tree
+chartInsert (KC tree) item key = fmap KC (rbmInsert key item tree)
+chartLookup (KC tree)      key = rbmLookup key tree
+chartList   (KC tree)          = concatMap snd (rbmList tree)
+--------------------------------------------------------------------------------}
+
+
+{--------------------------------------------------------------------------------
+-- key charts as unsorted association lists -- OBSOLETE!
+
+newtype Chart          item key = SC [(key, item)]
+
+emptyChart = SC []
+chartMember (SC chart) item key = (key,item) `elem` chart
+chartInsert (SC chart) item key = if (key,item) `elem` chart then Nothing else Just (SC ((key,item):chart))
+chartLookup (SC chart)      key = [ item | (key',item) <- chart, key == key' ]
+chartList   (SC chart)          = map snd chart
+--------------------------------------------------------------------------------}
+