fix(destructure): Destructuring doesn't default falsey values to undefined

Author: Ramanpreet Nara

package.json

@@ -1,6 +1,6 @@
 {
   "name": "glisp",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "A simple lisp interpreter in JS.",
   "main": "lib/index.js",
   "author": "Ramanpreet Nara",

src/evaluate/special-forms/fn.test.js

@@ -159,6 +159,14 @@ test('should default elements to undefined if they cannot be destructured', (ass
   assert.truthy(I.is(result, expected));
 });
 
+test('should accept falsey arguments', (assert) => {
+  const result = run({}, `
+    ((fn [x] x) false)
+  `);
+
+  assert.is(result, false);
+});
+
 function run(env, code) {
   return evaluate(env, parse(code));
 }

src/util/index.js

@@ -130,7 +130,7 @@ export function executableForm(name, ...body) {
 }
 
 export function zip(keys, values, factory) {
-  return keys.map((key, i) => [ key, values[i] || factory() ]);
+  return keys.map((key, i) => [ key, i >= values.length ? factory() : values[i] ]);
 }
 
 export function isGlobalRef(symbol) {