regexp-ast-analysis

What is regexp-ast-analysis?

The 'regexp-ast-analysis' npm package provides tools for analyzing and manipulating the abstract syntax tree (AST) of regular expressions. It allows developers to parse regular expressions into an AST, traverse and modify the AST, and perform various analyses on the structure of the regular expression.

What are regexp-ast-analysis's main functionalities?

Parsing Regular Expressions

This feature allows you to parse a regular expression into its corresponding AST. The code sample demonstrates how to parse the regular expression '/abc/' and output its AST structure.

const { parseRegExpLiteral } = require('regexp-ast-analysis');
const ast = parseRegExpLiteral('/abc/');
console.log(JSON.stringify(ast, null, 2));

Traversing the AST

This feature allows you to traverse the AST of a regular expression. The code sample demonstrates how to visit each character node in the AST and log its raw value.

const { parseRegExpLiteral, visitRegExpAST } = require('regexp-ast-analysis');
const ast = parseRegExpLiteral('/abc/');
visitRegExpAST(ast, {
  onCharacterEnter(node) {
    console.log('Character:', node.raw);
  }
});

Modifying the AST

This feature allows you to modify the AST of a regular expression. The code sample demonstrates how to change the character 'a' to 'x' in the AST.

const { parseRegExpLiteral, visitRegExpAST } = require('regexp-ast-analysis');
const ast = parseRegExpLiteral('/abc/');
visitRegExpAST(ast, {
  onCharacterEnter(node) {
    if (node.raw === 'a') {
      node.raw = 'x';
    }
  }
});
console.log(JSON.stringify(ast, null, 2));

Analyzing the AST

This feature allows you to perform various analyses on the AST of a regular expression. The code sample demonstrates how to analyze the AST of the regular expression '/a|b/' and output the analysis results.

const { parseRegExpLiteral, analyzeRegExpAST } = require('regexp-ast-analysis');
const ast = parseRegExpLiteral('/a|b/');
const analysis = analyzeRegExpAST(ast);
console.log(analysis);

Other packages similar to regexp-ast-analysis

regexpp

The 'regexpp' package is a regular expression parser and AST utility. It provides similar functionality to 'regexp-ast-analysis' in terms of parsing regular expressions into an AST and traversing the AST. However, 'regexpp' focuses more on providing a detailed and spec-compliant AST structure.

regexp-tree

The 'regexp-tree' package offers a toolkit for working with regular expressions, including parsing, transforming, and optimizing them. It provides similar AST manipulation capabilities as 'regexp-ast-analysis' but also includes additional features like regular expression optimization and code generation.

regex-parser

The 'regex-parser' package is a simple utility for parsing regular expressions into an AST. While it provides basic parsing functionality similar to 'regexp-ast-analysis', it lacks the advanced analysis and traversal features found in 'regexp-ast-analysis'.

README

RegExp AST analysis

This is a library providing functionalities to analyse JavaScript RegExp.

All functions operate on AST nodes produced by regexpp. Characters are parsed by refa.

Usage

Install the library using npm:

npm i regexp-ast-analysis

Import the library:

import * as RAA from "regexp-ast-analysis";

Documentation

Links to the full API documentation:

• Latest release
• Development

Changelog

0.4.1 (2022-04-17)

Improved

• canReorder can now prove more alternatives to be safe to reorder.
• canReorder will now create a cache if none is provided.