61 lines
1.4 KiB
JavaScript
61 lines
1.4 KiB
JavaScript
// Structure types
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(function(baselib) {
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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 (!(val in symbolCache)) {
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symbolCache[val] = new Symbol(val);
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} else {
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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); |