60 lines
1.5 KiB
JavaScript
60 lines
1.5 KiB
JavaScript
/*jslint devel: false, browser: true, unparam: true, vars: true, plusplus: true, maxerr: 500, indent: 4 */
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// Structure types
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(function (baselib) {
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"use strict";
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var exports = {};
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baselib.symbols = exports;
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//////////////////////////////////////////////////////////////////////
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// Symbols
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//////////////////////////////////////////////////////////////////////
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var Symbol = function (val) {
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this.val = val;
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};
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var symbolCache = {};
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// makeInstance: string -> Symbol.
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Symbol.makeInstance = function (val) {
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// To ensure that we can eq? symbols with equal values.
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if (!(symbolCache.hasOwnProperty(val))) {
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symbolCache[val] = new Symbol(val);
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}
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return symbolCache[val];
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};
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Symbol.prototype.equals = function (other, aUnionFind) {
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return other instanceof Symbol &&
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this.val === other.val;
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};
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Symbol.prototype.toString = function (cache) {
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return this.val;
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};
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Symbol.prototype.toWrittenString = function (cache) {
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return this.val;
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};
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Symbol.prototype.toDisplayedString = function (cache) {
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return this.val;
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};
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var isSymbol = function (x) { return x instanceof Symbol; };
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var makeSymbol = function (s) { return Symbol.makeInstance(s); };
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//////////////////////////////////////////////////////////////////////
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exports.Symbol = Symbol;
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exports.makeSymbol = makeSymbol;
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exports.isSymbol = isSymbol;
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}(this.plt.baselib)); |