Add ANTLR grammar rules for 'bye' and 'goodbye' with parser and listener updates

Week_3/main.py

@@ -0,0 +1,28 @@
+import sys
+from antlr4 import *
+
+from week3Listener import week3Listener
+from week3Lexer import week3Lexer
+from week3Parser import week3Parser
+
+from antlr4.tree.Trees import Trees
+
+def main(argv):
+    if len(argv) == 1 :
+        InputStream = StdinStream()
+    else :
+        inpname = argv[1]
+        InputStream = FileStream(inpname)
+
+    # create lexer, token stream and parser using the selected input
+    lexer = week3Lexer(InputStream)
+    tokstream = CommonTokenStream(lexer)
+    parser = week3Parser(tokstream)
+
+    tree = parser.start()
+
+    print(Trees.toStringTree(tree, None, parser))
+
+if __name__ == '__main__' :
+    main(sys.argv)
+