ANTLR Lab: learn, test, and experiment with ANTLR grammars online!

Welcome to the ANTLR lab, where you can learn about ANTLR or experiment with and test grammars! Just hit the button to try out the sample grammar.

To start developing with ANTLR, see getting started.

Feedback/issues welcome. Brought to you by Terence Parr, the maniac behind ANTLR.

Disclaimer: This website and related functionality are not meant to be used for private code, data, or other intellectual property. Assume everything you enter could become public! Grammars and input you enter are submitted to a unix box for execution and possibly persisted on disk or other mechanism. Please run antlr4-lab locally to avoid privacy concerns.

Lexer Parser Enter your grammar here using ANTLR notation, drag and drop a file, or select one from the drop-down list (https://github.com/antlr/grammars-v4). Put combined grammars in the Parser tab and erase content from the Lexer tab. Enter some input to the right and hit the Run button to test. Hover over red gutter annotation to see error messages.

Enter your grammar here using ANTLR notation, drag and drop a file, or select one from the drop-down list (https://github.com/antlr/grammars-v4). Put combined grammars in the Parser tab and erase content from the Lexer tab. Enter some input to the right and hit the Run button to test. Hover over red gutter annotation to see error messages.

Input

Start rule Enter a rule name here from your grammar to the left where parsing should begin for the input specified above. Hit Run to test.

program

Tool console

Parser console

Tree Hierarchy

Parser profile info