Rework module system

Don't require/allow naming a module, instead require that the importer
names it. Allow importing into the local scope with the name !Local.
Simplify namespacing logic. Updates all tests to reflect these changes.

src/Parser.hs

@@ -73,8 +73,6 @@ parseSingle input =
 
 parseProgramM :: ParserM [TricuAST]
 parseProgramM = do
-  skipMany topLevelNewline
-  moduleNode <- optional parseModuleM
   skipMany topLevelNewline
   importNodes <- many (do
     node <- parseImportM
@@ -83,16 +81,7 @@ parseProgramM = do
   skipMany topLevelNewline
   exprs <- sepEndBy parseOneExpression (some topLevelNewline)
   skipMany topLevelNewline
-  return (maybe [] (: []) moduleNode ++ importNodes ++ exprs)
-
-
-parseModuleM :: ParserM TricuAST
-parseModuleM = do
-  LModule moduleName <- satisfyM isModule
-  pure (SModule moduleName)
-  where
-    isModule (LModule _) = True
-    isModule _           = False
+  return (importNodes ++ exprs)
 
 parseImportM :: ParserM TricuAST
 parseImportM = do
@@ -266,12 +255,19 @@ parseSingleItemM = do
 
 parseVarM :: ParserM TricuAST
 parseVarM = do
-  satisfyM (\case LIdentifier _ -> True; _ -> False) >>= \case
+  token <- satisfyM (\case 
+    LNamespace _ -> True
+    LIdentifier _ -> True 
+    _ -> False)
+  case token of
+    LNamespace ns -> do
+      _ <- satisfyM (== LDot)
+      LIdentifier name <- satisfyM (\case LIdentifier _ -> True; _ -> False)
+      pure $ SVar (ns ++ "." ++ name)
     LIdentifier name
       | name == "t" || name == "!result" ->
         fail ("Reserved keyword: " ++ name ++ " cannot be assigned.")
-      | otherwise                         ->
-         pure (SVar name)
+      | otherwise -> pure (SVar name)
     _ -> fail "Unexpected token while parsing variable"
 
 parseIntLiteralM :: ParserM TricuAST