antlr4-python3-runtime

import os from antlr4 import InputStream, CommonTokenStream, ParseTreeWalker # --- BEGIN: Dummy generated classes for demonstration --- # In a real scenario, these would be generated by the ANTLR tool: # java -jar antlr-4.x.x-complete.jar -Dlanguage=Python3 MyGrammar.g4 class MyGrammarLexer: def __init__(self, input_stream): pass def getAllTokens(self): return [] class MyGrammarParser: def __init__(self, token_stream): pass def startRule(self): return None # Replace 'startRule' with your grammar's entry rule class MyGrammarListener: def enterEveryRule(self, ctx): pass def exitEveryRule(self, ctx): pass # ... other enter/exit methods for your grammar rules # --- END: Dummy generated classes --- # Assuming MyGrammar.g4 contains: # grammar MyGrammar; # startRule: 'hello' ID EOF; # ID: [a-zA-Z]+; # WS: [ \t\r\n]+ -> skip; def parse_input(text): input_stream = InputStream(text) lexer = MyGrammarLexer(input_stream) # Use your generated Lexer class stream = CommonTokenStream(lexer) parser = MyGrammarParser(stream) # Use your generated Parser class # Optionally, set up error handling # parser.removeErrorListeners() # parser.addErrorListener(MyCustomErrorListener()) tree = parser.startRule() # Call the entry rule of your grammar # Optionally, walk the parse tree with a listener or visitor # walker = ParseTreeWalker() # listener = MyGrammarListener() # Use your generated Listener/Visitor class # walker.walk(listener, tree) print(f"Parse tree: {tree.toStringTree(recog=parser)}") if __name__ == '__main__': # Simulate user input or a file content # For a real application, you might read from stdin or a file test_input = os.environ.get('ANTLR_TEST_INPUT', 'hello world') print(f"Parsing: '{test_input}'") parse_input(test_input) print("Note: In a real scenario, 'MyGrammarLexer' and 'MyGrammarParser' would be generated .py files from your .g4 grammar using the ANTLR Java tool.")