"Committed_by_peb"

src/GF/Formalism/Symbol.hs

@@ -0,0 +1,46 @@
+----------------------------------------------------------------------
+-- |
+-- Maintainer  : PL
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/04/11 13:52:50 $ 
+-- > CVS $Author: peb $
+-- > CVS $Revision: 1.1 $
+--
+-- Basic type declarations and functions to be used in grammar formalisms
+-----------------------------------------------------------------------------
+
+
+module GF.Formalism.Symbol where
+
+import GF.Infra.Print
+
+------------------------------------------------------------
+-- symbols
+
+data Symbol c t = Cat c | Tok t
+		  deriving (Eq, Ord, Show)
+
+symbol :: (c -> a) -> (t -> a) -> Symbol c t -> a
+symbol fc ft (Cat cat) = fc cat
+symbol fc ft (Tok tok) = ft tok
+
+mapSymbol :: (c -> d) -> (t -> u) -> Symbol c t -> Symbol d u
+mapSymbol fc ft = symbol (Cat . fc) (Tok . ft)
+
+------------------------------------------------------------
+-- pretty-printing
+
+instance (Print c, Print t) => Print (Symbol c t) where
+    prt = symbol prt (simpleShow . prt)
+	where simpleShow str = "\"" ++ concatMap mkEsc str ++ "\""
+	      mkEsc '\\' = "\\\\"
+	      mkEsc '\"' = "\\\""
+	      mkEsc '\n' = "\\n"
+	      mkEsc '\t' = "\\t"
+	      mkEsc chr  = [chr]
+    prtList = prtSep " "
+
+
+