Started with unions.

src/GF/Compile/Compile.hs

@@ -10,6 +10,7 @@ import Modules
 import ReadFiles
 import ShellState
 import MkResource
+import MkUnion
 
 -- the main compiler passes
 import GetGrammar
@@ -177,6 +178,9 @@ makeSourceModule opts env@(k,gr,can) mo@(i,mi) = case mi of
           mos = modules gr
       --- putp "  type checking reused" $ ioeErr $ showCheckModule mos mo2
       return $ (k,mo2)
+    MTUnion ty imps -> do
+      mo' <- ioeErr $ makeUnion gr i ty imps
+      compileSourceModule opts env mo'
     _ -> compileSourceModule opts env mo
   _ -> compileSourceModule opts env mo
  where

src/GF/Compile/GetGrammar.hs

@@ -79,5 +79,5 @@ oldLexer = map change . L.tokens where
     (L.PT p (L.TS s)) | elem s new -> (L.PT p (L.TV (init s ++ "Z")))
     _ -> t
   new = words $ "abstract concrete interface incomplete " ++ 
-                "instance out open resource reuse transfer with where"
+                "instance out open resource reuse transfer union with where"
 

src/GF/Compile/MkUnion.hs

@@ -0,0 +1,19 @@
+module MkUnion (makeUnion) where
+
+import Grammar
+import Ident
+import Modules
+import Macros
+import PrGrammar
+
+import Operations
+
+import Monad
+
+-- building union of modules
+-- AR 21/8/2002 -- 22/6/2003 for GF with modules
+
+makeUnion :: SourceGrammar -> Ident -> ModuleType Ident -> [(Ident,[Ident])] ->
+             Err SourceModule
+makeUnion gr m ty imps = do
+  Bad "Sorry: unions not yet implemented"