extended cf syntax; Det experiment

examples/CLE/CF2GF.hs

@@ -0,0 +1,20 @@
+import Data.List (intersperse)
+import Data.Char (isAlpha)
+
+-- to massage cf rules to funs, in order, preserving comments
+-- to get cats, use pg -printer=gf
+
+cf2gf :: FilePath -> IO ()
+cf2gf file = do
+  ss <- readFile file >>= return . lines
+  mapM_ (putStrLn . mkOne) ss
+
+mkOne line = case words line of
+  fun : cat : "::=" : cats -> 
+    let 
+      (cats0,cats2) = span (/=";") cats
+      cats1 = filter (isAlpha . head) cats0 ++ [cat] 
+    in
+    unwords $ [init fun, ":"] ++ intersperse "->" cats1 ++ cats2
+  _ -> line
+