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 regjsgen.generate in 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:
  - regjsgen.generate
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:8c036a23b12229f58c6f3cd1b8df7f7623b15925ff41046b63be4e885d170cd7","constraints":{"executionContext":"node"},"contract":["regjsgen.generate(node) generates RegExp pattern string from AST node","regjsgen.generate(node) serializes alternative, disjunction, and symbol value nodes","regjsgen.generate(node) serializes characterClass, characterClassRange, and characterClassEscape nodes","regjsgen.generate(node) serializes anchor and dot nodes","regjsgen.generate(node) serializes capturing, named, non-capturing, and lookaround group nodes","regjsgen.generate(node) serializes greedy and non-greedy quantifier nodes","regjsgen.generate(node) serializes indexed and named reference nodes","regjsgen.generate(node) serializes unicodePropertyEscape nodes","regjsgen.generate(node) throws Error when node type is invalid","regjsgen.generate(node) throws Error when value codePoint is invalid"],"goal":"verify regjsgen.generate in pkg:npm/regjsgen@0.8.0","kind":"HOW","packages":["pkg:npm/regjsgen@0.8.0"],"schemaVersion":1,"symbols":["regjsgen.generate"]},"contractCommand":["node","test/contract.cjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/regjsgen@0.8.0"],"schemaVersion":1,"subject":"pkg:npm/regjsgen@0.8.0","symbols":["regjsgen.generate"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-regjsgen",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-regjsgen",
      "version": "1.0.0",
      "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 for regjsgen",
  "main": "src/index.js",
  "dependencies": {
    "regjsgen": "0.8.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify regjsgen.generate in pkg:npm/regjsgen@0.8.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/regjsgen@0.8.0"
  ],
  "symbols": [
    "regjsgen.generate"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const regjsgen = require('regjsgen');

/**
 * Generate a regular expression string from an AST node.
 * @param {object} node - The AST node to generate regex from.
 * @returns {string} The serialized regular expression string.
 */
function generate(node) {
  return regjsgen.generate(node);
}

module.exports = {
  regjsgen,
  generate
};

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

// 1. regjsgen.generate(node) generates RegExp pattern string from AST node
assert.strictEqual(typeof regjsgen.generate, 'function');
assert.strictEqual(generate({ type: 'dot' }), '.');

// 2. regjsgen.generate(node) serializes alternative, disjunction, and symbol value nodes
const alt = {
  type: 'alternative',
  body: [
    { type: 'value', kind: 'symbol', codePoint: 97 },
    { type: 'value', kind: 'symbol', codePoint: 98 }
  ]
};
assert.strictEqual(regjsgen.generate(alt), 'ab');
assert.strictEqual(generate(alt), 'ab');

const disj = {
  type: 'disjunction',
  body: [
    { type: 'value', kind: 'symbol', codePoint: 97 },
    { type: 'value', kind: 'symbol', codePoint: 98 }
  ]
};
assert.strictEqual(regjsgen.generate(disj), 'a|b');

// 3. regjsgen.generate(node) serializes characterClass, characterClassRange, and characterClassEscape nodes
const charClass = {
  type: 'characterClass',
  negative: false,
  body: [
    {
      type: 'characterClassRange',
      min: { type: 'value', kind: 'symbol', codePoint: 97 },
      max: { type: 'value', kind: 'symbol', codePoint: 122 }
    },
    { type: 'characterClassEscape', value: 'd' }
  ]
};
assert.strictEqual(regjsgen.generate(charClass), '[a-z\\d]');

const negClass = {
  type: 'characterClass',
  negative: true,
  body: [{ type: 'value', kind: 'symbol', codePoint: 48 }]
};
assert.strictEqual(regjsgen.generate(negClass), '[^0]');

// 4. regjsgen.generate(node) serializes anchor and dot nodes
assert.strictEqual(regjsgen.generate({ type: 'anchor', kind: 'start' }), '^');
assert.strictEqual(regjsgen.generate({ type: 'anchor', kind: 'end' }), '$');
assert.strictEqual(regjsgen.generate({ type: 'anchor', kind: 'boundary' }), '\\b');
assert.strictEqual(regjsgen.generate({ type: 'anchor', kind: 'not-boundary' }), '\\B');
assert.strictEqual(regjsgen.generate({ type: 'dot' }), '.');

// 5. regjsgen.generate(node) serializes capturing, named, non-capturing, and lookaround group nodes
const namedGroup = {
  type: 'group',
  behavior: 'normal',
  name: { type: 'identifier', value: 'word' },
  body: [{ type: 'characterClassEscape', value: 'w' }]
};
assert.strictEqual(regjsgen.generate(namedGroup), '(?<word>\\w)');

const nonCapGroup = {
  type: 'group',
  behavior: 'ignore',
  body: [{ type: 'value', kind: 'symbol', codePoint: 97 }]
};
assert.strictEqual(regjsgen.generate(nonCapGroup), '(?:a)');

const lookahead = {
  type: 'group',
  behavior: 'lookahead',
  body: [{ type: 'value', kind: 'symbol', codePoint: 97 }]
};
assert.strictEqual(regjsgen.generate(lookahead), '(?=a)');

const negLookahead = {
  type: 'group',
  behavior: 'negativeLookahead',
  body: [{ type: 'value', kind: 'symbol', codePoint: 97 }]
};
assert.strictEqual(regjsgen.generate(negLookahead), '(?!a)');

const lookbehind = {
  type: 'group',
  behavior: 'lookbehind',
  body: [{ type: 'value', kind: 'symbol', codePoint: 97 }]
};
assert.strictEqual(regjsgen.generate(lookbehind), '(?<=a)');

const negLookbehind = {
  type: 'group',
  behavior: 'negativeLookbehind',
  body: [{ type: 'value', kind: 'symbol', codePoint: 97 }]
};
assert.strictEqual(regjsgen.generate(negLookbehind), '(?<!a)');

// 6. regjsgen.generate(node) serializes greedy and non-greedy quantifier nodes
const star = {
  type: 'quantifier',
  min: 0,
  max: null,
  greedy: true,
  body: [{ type: 'dot' }]
};
assert.strictEqual(regjsgen.generate(star), '.*');

const plus = {
  type: 'quantifier',
  min: 1,
  max: null,
  greedy: true,
  body: [{ type: 'dot' }]
};
assert.strictEqual(regjsgen.generate(plus), '.+');

const optional = {
  type: 'quantifier',
  min: 0,
  max: 1,
  greedy: true,
  body: [{ type: 'dot' }]
};
assert.strictEqual(regjsgen.generate(optional), '.?');

const rangeQuant = {
  type: 'quantifier',
  min: 2,
  max: 5,
  greedy: false,
  body: [{ type: 'characterClassEscape', value: 'd' }]
};
assert.strictEqual(regjsgen.generate(rangeQuant), '\\d{2,5}?');

// 7. regjsgen.generate(node) serializes indexed and named reference nodes
const numRef = {
  type: 'reference',
  matchIndex: 1
};
assert.strictEqual(regjsgen.generate(numRef), '\\1');

const namedRef = {
  type: 'reference',
  name: { type: 'identifier', value: 'word' }
};
assert.strictEqual(regjsgen.generate(namedRef), '\\k<word>');

// 8. regjsgen.generate(node) serializes unicodePropertyEscape nodes
const uProp = {
  type: 'unicodePropertyEscape',
  value: 'Letter',
  negative: false
};
assert.strictEqual(regjsgen.generate(uProp), '\\p{Letter}');

const negUProp = {
  type: 'unicodePropertyEscape',
  value: 'ASCII',
  negative: true
};
assert.strictEqual(regjsgen.generate(negUProp), '\\P{ASCII}');

// 9. regjsgen.generate(node) throws Error when node type is invalid
assert.throws(() => regjsgen.generate({ type: 'invalidType' }), /Invalid node type/);

// 10. regjsgen.generate(node) throws Error when value codePoint is invalid
assert.throws(() => regjsgen.generate({ type: 'value', kind: 'symbol', codePoint: 'invalid' }), /Invalid code point/);

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