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