The extension for ANTLR4 support in Visual Studio Code.
What's New
Externalized the formatter into an own Node.js package for broader use.
How To Contribute
If you want to create your own version of this extension or plan to contribute to its development then follow the steps outlined in the contribute.md document.
Features
Syntax Coloring
Syntax coloring for ANTLR grammars (.g and .g4 files)
Comes with an own beautiful color theme, which not only includes all the recommended groups, but also some special rules for grammar elements that you won't find in other themes (e.g. alt labels and options). They are, immodestly, named Complete Dark and Complete Light.
Code Completion + Symbol Information
Code suggestions for all rule + token names, channels, modes etc. (including built-in ones).
Symbol type + location are shown on mouse hover. Navigate to any symbol with Ctrl/Cmd + Click. This works even for nested grammars (token vocabulary + imports).
Symbol list for quick navigation (via Shift + Ctrl/Cmd + O).
Grammar Validations
In the background syntax checking takes place, while typing. Also some semantic checks are done, e.g. for duplicate or unknown symbols.
When parser generation is enabled (at least for internal use) ANTLR4 itself is used to check for errors and warnings. These are then reported instead of the internally found problems and give you so the full validation power of ANTLR4.
More Information
There are a number of documentation files for specific topics:
VS Code Extension for ANTLR4 Grammars
