regjsgen 0.8.0: generate

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/regjsgen@0.8.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/regjsgen@0.8.0
Demonstrate these symbols/APIs:
  - generate

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:4452fe08e43778af2cb443a4f4bf1bffa8daf97f153ee05f9fcd5b46f3eb573e","contract":["generate produces regular expression strings from AST nodes including character classes, ranges, and escapes","generate produces strings for anchors, quantifiers, disjunctions, and groups","generate throws Error for invalid node types or malformed nodes"],"goal":"verify pkg:npm/regjsgen@0.8.0","kind":"HOW","packages":["pkg:npm/regjsgen@0.8.0"],"schemaVersion":1,"symbols":["generate"]},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/regjsgen@0.8.0"],"schemaVersion":1,"subject":"pkg:npm/regjsgen@0.8.0","symbols":["generate"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-regjsgen",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-regjsgen",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "regjsgen": "0.8.0"
      }
    },
    "node_modules/regjsgen": {
      "version": "0.8.0",
      "resolved": "https://registry.npmjs.org/regjsgen/-/regjsgen-0.8.0.tgz",
      "integrity": "sha512-RvwtGe3d7LvWiDQXeQw8p5asZUmfU1G/l6WbUXeHta7Y2PEIvBTwH6E2EfmYUK8pxcxEdEmaomqyp0vZZ7C+3Q==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-regjsgen",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for regjsgen",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "regjsgen": "0.8.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/regjsgen@0.8.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/regjsgen@0.8.0"
  ],
  "symbols": [
    "generate"
  ]
}

const { generate } = require('regjsgen');

function generateRegex(ast) {
  return generate(ast);
}

module.exports = {
  generateRegex,
  generate
};

const assert = require('node:assert');
const { generate } = require('regjsgen');
const { generateRegex } = require('../src/index.js');

// 1. Value symbols and character classes
const charClassAst = {
  type: 'characterClass',
  negative: false,
  body: [
    {
      type: 'characterClassRange',
      min: { type: 'value', kind: 'symbol', codePoint: 97 },
      max: { type: 'value', kind: 'symbol', codePoint: 122 }
    },
    {
      type: 'characterClassRange',
      min: { type: 'value', kind: 'symbol', codePoint: 48 },
      max: { type: 'value', kind: 'symbol', codePoint: 57 }
    }
  ]
};
assert.strictEqual(generate(charClassAst), '[a-z0-9]', 'Should generate character class with ranges');
assert.strictEqual(generateRegex(charClassAst), '[a-z0-9]', 'Wrapper should return same result');

const negatedClassAst = {
  type: 'characterClass',
  negative: true,
  body: [
    { type: 'characterClassEscape', value: 'd' }
  ]
};
assert.strictEqual(generate(negatedClassAst), '[^\\d]', 'Should generate negated character class with escape');

// 2. Anchors, quantifiers, and disjunction
const regexAst = {
  type: 'alternative',
  body: [
    { type: 'anchor', kind: 'start' },
    {
      type: 'quantifier',
      min: 1,
      max: null,
      greedy: true,
      body: [
        { type: 'characterClassEscape', value: 'w' }
      ]
    },
    { type: 'anchor', kind: 'end' }
  ]
};
assert.strictEqual(generate(regexAst), '^\\w+$', 'Should generate anchored expression with quantifier');

const disjunctionAst = {
  type: 'disjunction',
  body: [
    {
      type: 'alternative',
      body: [
        { type: 'value', kind: 'symbol', codePoint: 102 },
        { type: 'value', kind: 'symbol', codePoint: 111 },
        { type: 'value', kind: 'symbol', codePoint: 111 }
      ]
    },
    {
      type: 'alternative',
      body: [
        { type: 'value', kind: 'symbol', codePoint: 98 },
        { type: 'value', kind: 'symbol', codePoint: 97 },
        { type: 'value', kind: 'symbol', codePoint: 114 }
      ]
    }
  ]
};
assert.strictEqual(generate(disjunctionAst), 'foo|bar', 'Should generate disjunction');

// 3. Groups (named, non-capturing, lookahead)
const namedGroupAst = {
  type: 'group',
  behavior: 'normal',
  name: { type: 'identifier', value: 'tag' },
  body: [
    { type: 'value', kind: 'symbol', codePoint: 97 }
  ]
};
assert.strictEqual(generate(namedGroupAst), '(?<tag>a)', 'Should generate named capturing group');

const nonCapturingGroupAst = {
  type: 'group',
  behavior: 'ignore',
  body: [
    { type: 'value', kind: 'symbol', codePoint: 98 }
  ]
};
assert.strictEqual(generate(nonCapturingGroupAst), '(?:b)', 'Should generate non-capturing group');

const lookaheadGroupAst = {
  type: 'group',
  behavior: 'lookahead',
  body: [
    { type: 'value', kind: 'symbol', codePoint: 99 }
  ]
};
assert.strictEqual(generate(lookaheadGroupAst), '(?=c)', 'Should generate positive lookahead');

// 4. Unicode property escapes and dot
const unicodePropAst = {
  type: 'unicodePropertyEscape',
  value: 'Letter',
  negative: false
};
assert.strictEqual(generate(unicodePropAst), '\\p{Letter}', 'Should generate unicode property escape');

const dotAst = { type: 'dot' };
assert.strictEqual(generate(dotAst), '.', 'Should generate dot');

// 5. Error handling on invalid node types
assert.throws(() => {
  generate({ type: 'unknownType' });
}, /Invalid node type/, 'Should throw on unknown node type');

assert.throws(() => {
  generate({ type: 'value', kind: 'symbol', codePoint: 'invalid' });
}, /Invalid code point/, 'Should throw on invalid code point in value');

console.log('Contract tests passed successfully.');