WIP build tools

.gitignore

@@ -33,6 +33,5 @@ node_modules
 .node_repl_history
 
 .DS_Store
+lib
 dist
-
-.nyc_output

.travis.yml

@@ -0,0 +1,20 @@
+language: node_js
+
+node_js:
+ - 5.10.1
+
+compiler: clang-3.6
+
+env:
+ - CXX=clang-3.6
+
+addons:
+ apt:
+ sources:
+ - llvm-toolchain-precise-3.6
+ - ubuntu-toolchain-r-test
+ packages:
+ - clang-3.6
+ - g++-4.8
+
+after_success: npm run coveralls

README.md

@@ -1,2 +1,2 @@
-# trivial-js-interpreter
+# The Super Tiny _Interpreter_
 Let's explain what a **closure** is by writing a JavaScript interpreter in JavaScript.

package.json

@@ -1,32 +1,39 @@
 {
- "name": "trivial-js-interpreter",
+ "name": "the-super-tiny-interpreter",
  "version": "1.0.0",
- "description": "",
- "main": "index.js",
+ "description": "Explain what a closure is by writing a JavaScript interpreter in JavaScript",
+ "main": "lib/index.js",
  "scripts": {
+ "clean": "rimraf lib coverage",
+ "build:babel": "babel src --out-dir lib --ignore __tests__",
  "test": "jest",
- "lint": "eslint src"
+ "coverage": "jest --coverage",
+ "coveralls": "npm run coverage && cat ./coverage/lcov.info | coveralls",
+ "lint": "eslint src",
+ "postinstall": "npm run clean && npm run lint && npm test && npm run coveralls && npm run build:babel"
  },
  "repository": {
  "type": "git",
- "url": "git+https://github.com/keyanzhang/trivial-js-interpreter.git"
+ "url": "git+https://github.com/keyanzhang/the-super-tiny-interpreter.git"
  },
  "keywords": [],
  "author": "Keyan Zhang <[email protected]> (http:https://keya.nz)",
  "license": "MIT",
  "bugs": {
- "url": "https://github.com/keyanzhang/trivial-js-interpreter/issues"
+ "url": "https://github.com/keyanzhang/the-super-tiny-interpreter/issues"
  },
- "homepage": "https://github.com/keyanzhang/trivial-js-interpreter#readme",
+ "homepage": "https://github.com/keyanzhang/the-super-tiny-interpreter#readme",
  "devDependencies": {
+ "babel-cli": "^6.7.5",
  "babel-core": "^6.7.6",
  "babel-eslint": "^6.0.2",
- "babel-jest": "^11.0.0",
+ "babel-jest": "^11.0.1",
  "babel-plugin-transform-flow-strip-types": "^6.7.0",
  "babel-polyfill": "^6.7.4",
  "babel-preset-es2015": "^6.6.0",
  "babel-preset-stage-0": "^6.5.0",
- "eslint": "^2.7.0",
+ "coveralls": "^2.11.9",
+ "eslint": "^2.8.0",
  "eslint-config-airbnb": "^7.0.0",
  "eslint-plugin-babel": "^3.2.0",
  "jest": "^0.1.40",
@@ -35,14 +42,17 @@
  "dependencies": {
  "babylon": "^6.7.0",
  "fbjs": "^0.8.0",
- "immutable": "^3.7.6"
+ "immutable": "^3.8.0"
  },
  "jest": {
  "unmockedModulePathPatterns": [
  "<rootDir>/node_modules/babylon",
  "<rootDir>/node_modules/immutable",
  "<rootDir>/node_modules/fbjs",
  "<rootDir>/src/utils"
+ ],
+ "testPathDirs": [
+ "<rootDir>/src"
  ]
  }
 }

samples/adder.js

@@ -1,3 +1,5 @@
-const adder = (x) => (y) => x + y;
-const add3 = adder(3);
-add3(39);
+(() => {
+ const adder = (x) => (y) => x + y;
+ const add3 = adder(3);
+ return add3(39);
+})();

src/Closure.js

@@ -19,11 +19,11 @@ const makeClosure = (params, body, defineTimeEnv) => ({
  * This is a little bit tricky and please feel free to ignore this part.
  *
  * Our arrow functions can be recursively defined. For instance,
- * in `const fact = (x) => (x < 2 ? 1 : x * fact(x - 1));`:
+ * in `const fact = (x) => (x < 2 ? 1 : x * fact(x - 1));`
  * we need to reference `fact` in the body of `fact` itself.
  *
- * If we create a "normal" closure for the function above, the `fact` in the body
- * will be unbound.
+ * If we create a "normal" closure for the function above, the `fact` (pun intended)
+ * in the body will be unbound.
  *
  * A quick fix is to update the environment with a reference to the closure itself.
  * For more information, check http:https://www.cs.indiana.edu/~dyb/papers/fixing-letrec.pdf
@@ -54,13 +54,13 @@ const applyClosure = (evaluator, closure, vals, callTimeEnv, isLexical = true) =
  if (!isLexical) {
  // Dynamic scope.
  // `callTimeEnv` is the latest binding information.
- const envForTheEvaluator = batchExtendEnv(params, vals, callTimeEnv);
+ const envForTheEvaluator = batchExtendEnv(params, vals, /* HEY LOOK AT ME → */ callTimeEnv);
  return evaluator(body, envForTheEvaluator);
  }
 
  // Lexical closure yo.
  // `defineTimeEnv` is the one that got extracted from the closure.
- const envForTheEvaluator = batchExtendEnv(params, vals, defineTimeEnv);
+ const envForTheEvaluator = batchExtendEnv(params, vals, /* HEY LOOK AT ME → */ defineTimeEnv);
  return evaluator(body, envForTheEvaluator);
 };
 

src/Interp/StatementInterp.js

@@ -44,7 +44,7 @@ const interp = (exp, env) => {
 
  if (init.type === 'ArrowFunctionExpression') {
  /*
- * TL;DR: it could be a letrec!
+ * TL;DR: it could be a `letrec`!
  *
  * A better way is to do a static analysis and to see whether the RHS
  * actually contains recursive definitions.
@@ -68,7 +68,7 @@ const interp = (exp, env) => {
  // case 'IfStatement': {
  // const { alternate, consequent, test } = currentExp;
  // const testVal = expInterp(test, currentEnv);
- // return currentExp;
+ //
  // if (testVal) {
  //
  // }

src/Parser.js

@@ -2,7 +2,7 @@
  * Writing a parser is way beyond the scope of this interpreter.
  * Let's just borrow it from babel.
  */
-import { parse as bParse } from 'babylon';
+import { parse as babylonParse } from 'babylon';
 import { isObject, mapFilterObject } from './utils';
 
 const defaultOptions = {
@@ -44,7 +44,7 @@ const cleanupAst = (target) => {
 };
 
 const parse = (code, options = defaultOptions) => {
- const originalAst = bParse(code, options);
+ const originalAst = babylonParse(code, options);
  return cleanupAst(originalAst).program; // we don't care about `File` type, too
 };
 

src/utils.js

@@ -9,7 +9,7 @@ const mapFilterObject = (obj, fn) => {
 
  keys.forEach((key) => {
  const val = obj[key];
- const fnResult = fn(val, key); // `fn` return `false` for removal, or a tuple of `[ key, val ]`
+ const fnResult = fn(val, key); // `fn` returns `false` for removal, or a tuple of `[ key, val ]`
  if (fnResult) {
  const [ newKey, newVal ] = fnResult;
  result[newKey] = newVal;