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55 lines
1.3 KiB
55 lines
1.3 KiB
var SyntaxError = require('./SyntaxError'); |
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var TAB = 9; |
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var N = 10; |
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var F = 12; |
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var R = 13; |
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var SPACE = 32; |
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var Tokenizer = function(str) { |
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this.str = str; |
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this.pos = 0; |
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}; |
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Tokenizer.prototype = { |
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charCodeAt: function(pos) { |
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return pos < this.str.length ? this.str.charCodeAt(pos) : 0; |
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}, |
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charCode: function() { |
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return this.charCodeAt(this.pos); |
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}, |
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nextCharCode: function() { |
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return this.charCodeAt(this.pos + 1); |
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}, |
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nextNonWsCode: function(pos) { |
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return this.charCodeAt(this.findWsEnd(pos)); |
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}, |
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findWsEnd: function(pos) { |
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for (; pos < this.str.length; pos++) { |
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var code = this.str.charCodeAt(pos); |
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if (code !== R && code !== N && code !== F && code !== SPACE && code !== TAB) { |
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break; |
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} |
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} |
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return pos; |
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}, |
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substringToPos: function(end) { |
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return this.str.substring(this.pos, this.pos = end); |
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}, |
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eat: function(code) { |
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if (this.charCode() !== code) { |
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this.error('Expect `' + String.fromCharCode(code) + '`'); |
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} |
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this.pos++; |
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}, |
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peek: function() { |
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return this.pos < this.str.length ? this.str.charAt(this.pos++) : ''; |
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}, |
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error: function(message) { |
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throw new SyntaxError(message, this.str, this.pos); |
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} |
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}; |
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module.exports = Tokenizer;
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