Part of the Next Generation ANTLR Project

Custom ANTLR4 Code Generator

This package contains a custom code generator for ANTLR4 grammars. It is based on the official ANTLR4 code generator, but includes support for the antlr4ng runtime, so the TypeScript output is different. Other than that it is a drop-in replacement for the official generator and can also be used with the official runtimes (C++, Java, etc.).

Installation

To install the package, run the following command:

npm install antlr4ng-cli

Usage

The package needs Java installed on your system, To generate your parser, run the following command:

antlr4ng <options> <grammar-file>

in the root of your project, where you installed the package.

Note: in contrast to antlr4ts you have to specify the target language explicitly, just as if you use the generator jar file directly. A typical case would be:

antlr4ng -Dlanguage=TypeScript -o generated/ -visitor -listener -Xexact-output-dir path/to/YourLexer.g4 path/to/YourParser.g4

Release Notes

2.0.0

This is the next major release of the code generator, after an overhaul of the antlr4ng runtime. It introduces a number of API changes, but no changes to the original working mechanism. The other targets (C++, Java, etc.) are not affected by this release. All changes in this release are to support the new antlr4ng major release 3.0.0:

• Renamed class members (_type -> type, _channel -> channel, _mode -> mode, _parseListeners -> parseListeners).
• Specialized getText methods for the token stream, to avoid frequent parameter checking in method overloading.
• Merged the class RuleContext into ParserRuleContext. It's not used anywhere else, so why keeping it around?
• ParserRuleContext.exception has been removed and it is no longer set in generated code (only relevant for error conditions, where a proper exception is passed to error listeners.
• More non-null assertions and null-safety checks have been added (mostly relevant for local rule variables and return values).

1.0.7

Code generation improvements, especially for local rule attributes. Attributes in a rule (which are implemented as local variables in the generated code) can be unassigned and need extra null-safety checks (the ? operator) or non-null assertions. The code generator now adds these checks automatically.

1.0.5 - 1.0.6

Code generation changes:

• Local attributes in rule contexts are now made optional, to account for the fact that they are not always set.

1.0.4

Compatible with antlr4ng 2.0.0

Code generation changes:

• More locations where the override keyword is needed in generated classes.
• ParserRuleContext._ctx was renamed to ParserRuleContext.context in the runtime.
• Optional null result for listener/walker methods.
• TokenStream.getText no longer needs a temporary interval as parameter, but can directly work with start and stop values.

1.0.3

• Non-optional token members of a rule context no longer return null, which makes explicit non-null assertions in user code unnecessary.
• Added override keyword for generated copyFrom methods.

1.0.2

Updated the ANTLR4 jar.

1.0.1

• Some changes for renamed class members in the runtime (e.g. _interp -> interpreter).

1.0.0

• Initial release.