├── .babelrc ├── .gitignore ├── .npmignore ├── .travis.yml ├── LICENSE ├── README.md ├── package.json ├── src └── index.js └── test ├── fixtures ├── basic │ ├── .babelrc │ ├── actual.js │ └── expected.js ├── combined │ ├── .babelrc │ ├── actual.js │ └── expected.js ├── complex │ ├── .babelrc │ ├── actual.js │ └── expected.js └── nested │ ├── .babelrc │ ├── actual.js │ └── expected.js └── index.js /.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "presets": ["es2015", "stage-0"] 3 | } 4 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | node_modules 2 | *.log 3 | lib 4 | -------------------------------------------------------------------------------- /.npmignore: -------------------------------------------------------------------------------- 1 | node_modules 2 | *.log 3 | src 4 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: node_js 2 | node_js: 3 | - v6 4 | - v7 5 | - v8 6 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # babel-plugin-overload 2 | 3 | [![CircleCI](https://circleci.com/gh/foxbenjaminfox/babel-plugin-overload/tree/master.svg?style=shield)](https://circleci.com/gh/foxbenjaminfox/babel-plugin-overload/tree/master) 4 | 5 | This is an experimental plugin that allows you to overload operators in your Javascript code. 6 | 7 | Compare with Python: 8 | 9 | ````py 10 | class Addable: 11 | def __add__(self, other): 12 | return # some computation which uses self and other 13 | ```` 14 | 15 | Using this Babel plugin: 16 | ````js 17 | class Addable { 18 | [Symbol.for('+')] (other) { 19 | return // some computation which uses this and other 20 | } 21 | } 22 | ```` 23 | 24 | This plugin is still in beta and should be considered highly experimental. It should go without saying that you probably should not use this in production. 25 | 26 | ## Example 27 | 28 | **In** 29 | 30 | ````js 31 | x + y 32 | ```` 33 | 34 | **Out** 35 | 36 | ````js 37 | function (_left, _right) { 38 | if (_left !== null && _left !== undefined && _left[Symbol.for("+")]) return _left[Symbol.for("+")](_right);else return _left + _right; 39 | }(x, y); 40 | ```` 41 | 42 | ## Supported Operators 43 | At the moment, all binary operators are supported. Unary operators are coming soon. 44 | 45 | The full supported list is: 46 | - The arithmetic operators: `+`, `-`, `/`, `*`, `%`, `**` 47 | - The bitwise operators: `&`, `|`, `^` 48 | - The bitshift operators: `>>`, `<<`, `>>>`, `<<<` 49 | - The equality operators: `==`, `===`, `!=`, `!==` 50 | - The inequality operators: `>`, `<`, `>=`, `<=` 51 | - The remaining miscellaneous operators: `in` and `instanceof` 52 | 53 | To overload any of them, define a method named with the Symbol you get with `Symbol.for` for the appropriate operator. For instance, use `Symbol.for('+')` to overload the `+` operator, and `Symbol.for('in')` to overload the `in` operator. 54 | 55 | You can define the overloading method on the object itself or anywhere on the object's prototype chain. 56 | 57 | At the moment, overloading is only supported for the left side value. Support for overloading on the right side value (the equivalent of Python's `__radd__` family of methods) is coming soon. 58 | 59 | ## Installation 60 | 61 | ````sh 62 | $ npm install babel-plugin-overload 63 | ```` 64 | 65 | ## Usage 66 | 67 | ### Via `.babelrc` (Recommended) 68 | 69 | **.babelrc** 70 | 71 | ```json 72 | { 73 | "plugins": ["overload"] 74 | } 75 | ``` 76 | 77 | ### Via CLI 78 | 79 | ```sh 80 | $ babel --plugins overload script.js 81 | ``` 82 | 83 | ### Via Node API 84 | 85 | ````javascript 86 | require("babel-core").transform("code", { 87 | plugins: ["overload"] 88 | }); 89 | ```` 90 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "version": "0.0.2", 3 | "name": "babel-plugin-overload", 4 | "description": "Operator overloading plugin for babel", 5 | "repository": "foxbenjaminfox/babel-plugin-overload", 6 | "author": "Benjamin Fox ", 7 | "license": "Apache-2.0", 8 | "main": "lib/index.js", 9 | "scripts": { 10 | "clean": "rm -rf lib", 11 | "build": "babel src -d lib", 12 | "test": "mocha --compilers js:babel-register", 13 | "test:watch": "npm run test -- --watch", 14 | "postbuild": "npm run test", 15 | "prepublish": "npm run clean && npm run build", 16 | "patch": "npm version patch && npm publish", 17 | "minor": "npm version minor && npm publish", 18 | "major": "npm version major && npm publish", 19 | "postpublish": "git push origin master --follow-tags" 20 | }, 21 | "keywords": [ 22 | "operator", 23 | "overload", 24 | "operator-overloading", 25 | "babel-plugin" 26 | ], 27 | "devDependencies": { 28 | "babel-cli": "^6.18.0", 29 | "babel-core": "^6.22.1", 30 | "babel-preset-es2015": "^6.18.0", 31 | "babel-preset-stage-0": "^6.3.13", 32 | "babel-register": "^6.22.0", 33 | "babel-template": "^6.16.0", 34 | "mocha": "^2.2.5" 35 | } 36 | } 37 | -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | import template from 'babel-template' 2 | 3 | function invokedTemplate(op) { 4 | return template(` 5 | (function (LEFT_ARG, RIGHT_ARG) { 6 | if (LEFT_ARG !== null && LEFT_ARG !== undefined 7 | && LEFT_ARG[Symbol.for("${op}")]) 8 | return LEFT_ARG[Symbol.for("${op}")](RIGHT_ARG) 9 | else return LEFT_ARG ${op} RIGHT_ARG 10 | }) 11 | `) 12 | } 13 | export default function({ types: t }) { 14 | return { 15 | visitor: { 16 | BinaryExpression (path) { 17 | if (path.node.hasOwnProperty('_fromTemplate')) return 18 | 19 | const func = invokedTemplate(path.node.operator)({ 20 | LEFT_ARG: path.scope.generateUidIdentifier("left"), 21 | RIGHT_ARG: path.scope.generateUidIdentifier("right"), 22 | }).expression 23 | 24 | path.replaceWith( 25 | t.callExpression( 26 | func, 27 | [path.node.left, path.node.right] 28 | ) 29 | ) 30 | } 31 | } 32 | } 33 | } 34 | -------------------------------------------------------------------------------- /test/fixtures/basic/.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "plugins": [ 3 | ["../../../src"] 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /test/fixtures/basic/actual.js: -------------------------------------------------------------------------------- 1 | let foo = x + y; 2 | -------------------------------------------------------------------------------- /test/fixtures/basic/expected.js: -------------------------------------------------------------------------------- 1 | let foo = function (_left, _right) { 2 | if (_left !== null && _left !== undefined && _left[Symbol.for("+")]) return _left[Symbol.for("+")](_right);else return _left + _right; 3 | }(x, y); -------------------------------------------------------------------------------- /test/fixtures/combined/.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "plugins": [ 3 | ["../../../src"] 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /test/fixtures/combined/actual.js: -------------------------------------------------------------------------------- 1 | let foo = (x * y) / (a + b - c); 2 | -------------------------------------------------------------------------------- /test/fixtures/combined/expected.js: -------------------------------------------------------------------------------- 1 | let foo = function (_left, _right) { 2 | if (_left !== null && _left !== undefined && _left[Symbol.for("/")]) return _left[Symbol.for("/")](_right);else return _left / _right; 3 | }(function (_left2, _right2) { 4 | if (_left2 !== null && _left2 !== undefined && _left2[Symbol.for("*")]) return _left2[Symbol.for("*")](_right2);else return _left2 * _right2; 5 | }(x, y), function (_left3, _right3) { 6 | if (_left3 !== null && _left3 !== undefined && _left3[Symbol.for("-")]) return _left3[Symbol.for("-")](_right3);else return _left3 - _right3; 7 | }(function (_left4, _right4) { 8 | if (_left4 !== null && _left4 !== undefined && _left4[Symbol.for("+")]) return _left4[Symbol.for("+")](_right4);else return _left4 + _right4; 9 | }(a, b), c)); -------------------------------------------------------------------------------- /test/fixtures/complex/.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "plugins": [ 3 | ["../../../src"] 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /test/fixtures/complex/actual.js: -------------------------------------------------------------------------------- 1 | let foo = f(a + b) / 2 + w * g(x * y) + typeof (f - g); 2 | -------------------------------------------------------------------------------- /test/fixtures/complex/expected.js: -------------------------------------------------------------------------------- 1 | let foo = function (_left, _right) { 2 | if (_left !== null && _left !== undefined && _left[Symbol.for("+")]) return _left[Symbol.for("+")](_right);else return _left + _right; 3 | }(function (_left2, _right2) { 4 | if (_left2 !== null && _left2 !== undefined && _left2[Symbol.for("+")]) return _left2[Symbol.for("+")](_right2);else return _left2 + _right2; 5 | }(function (_left3, _right3) { 6 | if (_left3 !== null && _left3 !== undefined && _left3[Symbol.for("/")]) return _left3[Symbol.for("/")](_right3);else return _left3 / _right3; 7 | }(f(function (_left4, _right4) { 8 | if (_left4 !== null && _left4 !== undefined && _left4[Symbol.for("+")]) return _left4[Symbol.for("+")](_right4);else return _left4 + _right4; 9 | }(a, b)), 2), function (_left5, _right5) { 10 | if (_left5 !== null && _left5 !== undefined && _left5[Symbol.for("*")]) return _left5[Symbol.for("*")](_right5);else return _left5 * _right5; 11 | }(w, g(function (_left6, _right6) { 12 | if (_left6 !== null && _left6 !== undefined && _left6[Symbol.for("*")]) return _left6[Symbol.for("*")](_right6);else return _left6 * _right6; 13 | }(x, y)))), typeof function (_left7, _right7) { 14 | if (_left7 !== null && _left7 !== undefined && _left7[Symbol.for("-")]) return _left7[Symbol.for("-")](_right7);else return _left7 - _right7; 15 | }(f, g)); -------------------------------------------------------------------------------- /test/fixtures/nested/.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "plugins": [ 3 | ["../../../src"] 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /test/fixtures/nested/actual.js: -------------------------------------------------------------------------------- 1 | let foo = x + y + z; 2 | -------------------------------------------------------------------------------- /test/fixtures/nested/expected.js: -------------------------------------------------------------------------------- 1 | let foo = function (_left, _right) { 2 | if (_left !== null && _left !== undefined && _left[Symbol.for("+")]) return _left[Symbol.for("+")](_right);else return _left + _right; 3 | }(function (_left2, _right2) { 4 | if (_left2 !== null && _left2 !== undefined && _left2[Symbol.for("+")]) return _left2[Symbol.for("+")](_right2);else return _left2 + _right2; 5 | }(x, y), z); -------------------------------------------------------------------------------- /test/index.js: -------------------------------------------------------------------------------- 1 | import path from 'path'; 2 | import fs from 'fs'; 3 | import assert from 'assert'; 4 | import { transformFileSync } from 'babel-core'; 5 | import plugin from '../src'; 6 | 7 | function trim(str) { 8 | return str.replace(/^\s+|\s+$/, ''); 9 | } 10 | 11 | describe('Operator overloading', () => { 12 | const fixturesDir = path.join(__dirname, 'fixtures'); 13 | fs.readdirSync(fixturesDir).map((caseName) => { 14 | it(`should replace ${caseName.split('-').join(' ')} operators`, () => { 15 | const fixtureDir = path.join(fixturesDir, caseName); 16 | const actualPath = path.join(fixtureDir, 'actual.js'); 17 | const actual = transformFileSync(actualPath).code; 18 | 19 | const expected = fs.readFileSync( 20 | path.join(fixtureDir, 'expected.js') 21 | ).toString(); 22 | 23 | assert.equal(trim(actual), trim(expected)); 24 | }); 25 | }); 26 | }); 27 | --------------------------------------------------------------------------------