antlr4ng

library3.0.16jsnpmunverified

antlr4ng is an alternative, TypeScript-first runtime for ANTLR4 grammars, specifically designed to be used with the `antlr-ng` parser generation tool. Currently stable at version `3.0.16`, it receives frequent point releases addressing bugs and introducing minor enhancements. Unlike the original ANTLR4 JavaScript runtime, `antlr4ng` operates identically across Node.js and browser environments and is built with strict TypeScript nullability checks. It requires an ES2022 (ES6) compatible runtime for features like static initialization blocks and private class fields. While implementing nearly all features of the Java ANTLR4 runtime, it notably omits the `UnbufferedCharStream` class. Developers migrating from other ANTLR4 JavaScript runtimes will need to adjust code for stricter null handling and renamed internal members.

serialization web-framework

npm install antlr4ng

github ↗package ↗

INSTALL

IMPORT

SIG · ANTLR4NG

antlr4ng

serializationjavascriptv3.0.16

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

CharStream

✓ import { CharStream } from "antlr4ng";

✗ const { CharStream } = require("antlr4ng");

The `antlr4ng` package is an ES Module (ESM) and requires an `import` statement. It mandates ES2022+ features for its internal implementation.

CommonTokenStream

✓ import { CommonTokenStream } from "antlr4ng";

✗ const { CommonTokenStream } = require("antlr4ng");

Part of the core `antlr4ng` runtime for managing tokens from a lexer, typically used in conjunction with a `CharStream`.

ExpressionLexer

✓ import { ExpressionLexer } from "./generated/ExpressionLexer.js";

✗ import { ExpressionLexer } from "antlr4ng"; import { ExpressionLexer } from "./generated/ExpressionLexer";

Lexer, parser, and visitor classes are generated by the `antlr-ng` tool into user-defined paths. When using Node.js with ESM, the `.js` extension must be explicitly included in the import path.

Parser

✓ import { Parser } from "antlr4ng";

✗ const { Parser } = require("antlr4ng");

The base class for generated parsers, often extended for custom logic. It follows ESM import rules and ES2022+ requirements.

Demonstrates parsing a simple arithmetic expression using generated lexer and parser, highlighting basic setup with `CharStream` and `CommonTokenStream` from `antlr4ng`.

import { CharStream, CommonTokenStream } from "antlr4ng"; import { ExpressionLexer } from "./generated/ExpressionLexer.js"; import { ExpressionParser } from "./generated/ExpressionParser.js"; const input = "1 + 2 * 3"; const inputStream = CharStream.fromString(input); const lexer = new ExpressionLexer(inputStream); const tokenStream = new CommonTokenStream(lexer); const parser = new ExpressionParser(tokenStream); // Optionally configure error handling or listeners // parser.removeErrorListeners(); // parser.addErrorListener(new MyErrorListener()); const tree = parser.start(); // To demonstrate visitor usage (assuming MyVisitor is defined): // import { ExpressionVisitor } from "./generated/ExpressionVisitor.js"; // import { AddContext } from "./generated/ExpressionParser.js"; // Example context type // // class MyVisitor extends ExpressionVisitor<number> { // public visitAdd = (ctx: AddContext): number => { // // Assuming visit is implemented for other rule contexts // return this.visit(ctx.expression(0)) + this.visit(ctx.expression(1)); // }; // // ... implement other visit methods // protected defaultResult(): number { return 0; } // protected aggregateResult(aggregate: number, nextResult: number): number { return nextResult; } // } // const result = new MyVisitor().visit(tree); // console.log(`Parse tree successfully created. Visitor result: ${result}`); console.log("Parse tree successfully created.");

Debug

Known issues

breakingThe `antlr4ng` runtime requires ES2022 (ES13) or newer JavaScript environments, utilizing features like static initialization blocks and private class fields (`#field`). Older JavaScript runtimes (e.g., Node.js < 16) will fail.

fix

Ensure your Node.js version is 16.x or higher, or configure your bundler/TypeScript compiler to target `ES2022` or higher.

affects: >=3.0.0

breakingMigration from other ANTLR4 JavaScript runtimes requires adjusting code due to `antlr4ng`'s stricter TypeScript nullability. Many previously implicitly nullable members are now explicitly typed as nullable, aligning with Java runtime behavior.

fix

Implement explicit null checks (`if (member !== null)`) or use TypeScript's non-null assertion operator (`member!`) where appropriate, prioritizing safety.

affects: >=3.0.0

breakingSeveral internal parser and recognizer member variables have been renamed for consistency with TypeScript conventions (e.g., `_ctx` to `context`, `_errHandler` to `errorHandler`, `_input` to `inputStream`, `_interp` to `interpreter`).

fix

Update references to these renamed members throughout your custom parser logic, error handlers, or visitor/listener implementations.

affects: >=3.0.0

gotchaThis `antlr4ng` runtime is designed to be used with parsers generated by the `antlr-ng` tool. While it implements ANTLR4, direct compatibility with parsers generated by the original ANTLR4 JavaScript target might not be guaranteed due to numerous bug fixes and internal changes.

fix

Always use the `antlr-ng` tool to generate your lexer and parser files for optimal compatibility with the `antlr4ng` runtime.

affects: >=3.0.0

gotchaWhen importing generated lexer/parser/visitor files in an ESM Node.js environment, the `.js` extension must be explicitly included in the import path, even if the source file is `.ts`.

fix

Change `import { MyLexer } from './MyLexer';` to `import { MyLexer } from './MyLexer.js';` for generated files.

affects: >=3.0.0

Errors

Common errors & fixes

TS2339: Property '_ctx' does not exist on type 'Parser'. Did you mean 'context'?

Accessing an old, renamed internal member of `Parser` or `Recognizer`.

fix

Replace `parser._ctx` with `parser.context`. Similarly, change `_errHandler` to `errorHandler`, `_input` to `inputStream`, and `_interp` to `interpreter`.

TypeError: Class constructor CharStream cannot be invoked without 'new'

Attempting to use `require()` for the `antlr4ng` package, which is an ESM-only library and relies on ES2022+ features, or incorrect CJS interop.

fix

Ensure your project is configured for ES Modules and use `import { CharStream } from 'antlr4ng';` instead of `const { CharStream } = require('antlr4ng');`.

Error: Cannot find module './generated/ExpressionLexer'

The import path for generated files is incorrect, or the `.js` extension is missing when running in an ESM Node.js environment.

fix

Verify the relative path to your `generated` folder. For ESM in Node.js, ensure the import statement includes the `.js` extension: `import { ExpressionLexer } from './generated/ExpressionLexer.js';`

SyntaxError: Private field '#field' must be declared in an enclosing class

Running `antlr4ng` in a JavaScript environment that does not support ES2022 (ES13) features, specifically private class fields (`#field`).

fix

Upgrade your Node.js runtime to version 16.x or newer, or ensure your build tools (e.g., Babel, TypeScript compiler) are configured to transpile to a target that supports ES2022 or higher.

Upgrade

Version history

3.0.16latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

25 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/mike-lischke/antlr4ng ↗

packagehttps://www.npmjs.com/package/antlr4ng ↗