Switch underlying set implementation to ES6

Author: hezyin

src/numset.js

@@ -18,7 +18,8 @@ if (typeof define !== 'function') {
 }
 
 define(function (require, exports) {
-    var impl = require('./olist');
+    // var impl = require('./olist');
+    var impl = require('./set');
 
     for (var p in impl)
         exports[p] = impl[p];

src/set.js

@@ -0,0 +1,170 @@
+/*******************************************************************************
+ * Copyright (c) 2013 Max Schaefer
+ * Copyright (c) 2018 Persper Foundation
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *******************************************************************************/
+
+/*
+ * Keep the interface of ./olist.js, but use ES6 Set under the hood
+ */
+
+function size(s) {
+    if (typeof s === 'undefined')
+        return 0;
+
+    if (typeof s === 'number')
+        return 1;
+
+    return s.size;
+}
+
+/* Check whether set s contains number n */
+function contains(s, n) {
+    if (typeof s === 'undefined')
+        return false;
+
+    if (typeof s === 'number')
+        return s === n;
+
+    return s.has(n);
+}
+
+/* Add number n to set s, and return the possibly modified s */
+function add(s, n) {
+    if (typeof s === 'undefined')
+        return n;
+
+    if (typeof s === 'number')
+        return new Set([s, n]);
+
+    s.add(n);
+    return s;
+}
+
+/*
+ * Add all elements in set s2 to set s1, return the resulting set
+ * While set s1 may be modified, set s2 never is.
+ */
+function addAll(s1, s2) {
+    if (typeof s1 === 'undefined')
+        return copy(s2);
+
+    if (typeof s2 === 'undefined')
+        return s1;
+
+    if (typeof s1 === 'number' && typeof s2 === 'number') {
+        return new Set([s1, s2]);
+    }
+    else if (typeof s1 === 'number' && typeof s2 === 'object') {
+        return new Set([s1, ...s2]);
+    }
+    else if (typeof s1 === 'object' && typeof s2 === 'number') {
+        s1.add(s2);
+        return s1;
+    }
+    else {
+        for (let n of s2)
+            s1.add(n);
+        return s1
+    }
+}
+
+/*
+ * Remove number n from set s and return the modified set
+ * Pitfall: this remove is inplace for array, not inplace for number
+ */
+function remove(s, n) {
+    if (typeof s === 'undefined')
+        return s;
+
+    if (typeof s === 'number')
+        return s === n ? void(0) : s;
+
+    s.delete(n)
+    return s;
+}
+
+/*
+ * Remove all elements in set s2 from set s1, return the resulting set
+ */
+function removeAll(s1, s2) {
+    if (typeof s1 === 'undefined' || typeof s2 === 'undefined')
+        return s1;
+
+    if (typeof s1 === 'number')
+        return contains(s2, s1) ? void(0) : s1;
+
+    if (typeof s2 === 'number') {
+        s1.delete(s2);
+        return s1;
+    }
+
+    for (let n of s2)
+        s1.delete(n);
+
+    if (s1.size === 0)
+        return void(0);
+    else
+        return s1;
+}
+
+function copy(s) {
+    if (typeof s === 'undefined' || typeof s === 'number')
+        return s;
+
+    // Return a shallow clone of the original set s
+    return new Set(s);
+}
+
+function iter(s, cb) {
+    if (typeof s !== 'undefined') {
+        if (typeof s === 'number')
+            cb(s);
+        else
+            s.forEach(cb);
+    }
+}
+
+function map(s, f) {
+    if (typeof s !== 'undefined') {
+        if (typeof s === 'number')
+            return [f(s)];
+        else {
+            return Array.from(s).map(f);
+        }
+    }
+    else {
+        return [];
+    }
+}
+
+function fromArray(ary) {
+    return new Set(ary);
+}
+
+function toArray(s) {
+    if (typeof s === 'undefined')
+        return []
+
+    if (typeof s === 'number')
+        return [s]
+
+    return Array.from(s);
+}
+
+module.exports.size = size;
+module.exports.copy = copy;
+module.exports.contains = contains;
+module.exports.add = add;
+module.exports.addAll = addAll;
+module.exports.remove = remove;
+module.exports.removeAll = removeAll;
+module.exports.iter = iter;
+module.exports.map = map;
+module.exports.fromArray = fromArray;
+module.exports.toArray = toArray;
+