added the expression type

src/runtime/haskell/PGF.hs

@@ -1,6 +1,42 @@
-module PGF (PGF2.PGF, readPGF
+module PGF ( PGF2.PGF, readPGF
+           , abstractName
+
+           , CId, mkCId, wildCId, showCId, readCId
+
+           , categories
+           , functions, functionsByCat
+
+           , PGF2.Expr(..), PGF2.Literal(..), Tree
+
+           , PGF2.Type, PGF2.Hypo
            ) where
 
 import qualified PGF2 as PGF2
 
+newtype CId = CId String deriving (Show,Read,Eq,Ord)
+
+type Language = CId
+
 readPGF = PGF2.readPGF
+
+
+readLanguage = readCId
+showLanguage (CId s) = s
+
+
+abstractName gr = CId (PGF2.abstractName gr)
+
+
+categories gr = map CId (PGF2.categories gr)
+
+
+functions gr  = map CId (PGF2.functions gr)
+functionsByCat gr (CId c) = map CId (PGF2.functionsByCat gr c)
+
+type Tree = PGF2.Expr
+
+
+mkCId x = CId x
+wildCId = CId "_"
+showCId (CId x) = x
+readCId s = Just (CId s)