244 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			244 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| var charCodeDef = require('./char-code-definitions');
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| var isDigit = charCodeDef.isDigit;
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| var isHexDigit = charCodeDef.isHexDigit;
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| var isUppercaseLetter = charCodeDef.isUppercaseLetter;
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| var isName = charCodeDef.isName;
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| var isWhiteSpace = charCodeDef.isWhiteSpace;
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| var isValidEscape = charCodeDef.isValidEscape;
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| 
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| function getCharCode(source, offset) {
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|     return offset < source.length ? source.charCodeAt(offset) : 0;
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| }
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| 
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| function getNewlineLength(source, offset, code) {
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|     if (code === 13 /* \r */ && getCharCode(source, offset + 1) === 10 /* \n */) {
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|         return 2;
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|     }
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| 
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|     return 1;
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| }
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| 
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| function cmpChar(testStr, offset, referenceCode) {
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|     var code = testStr.charCodeAt(offset);
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| 
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|     // code.toLowerCase() for A..Z
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|     if (isUppercaseLetter(code)) {
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|         code = code | 32;
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|     }
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| 
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|     return code === referenceCode;
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| }
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| 
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| function cmpStr(testStr, start, end, referenceStr) {
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|     if (end - start !== referenceStr.length) {
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|         return false;
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|     }
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| 
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|     if (start < 0 || end > testStr.length) {
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|         return false;
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|     }
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| 
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|     for (var i = start; i < end; i++) {
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|         var testCode = testStr.charCodeAt(i);
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|         var referenceCode = referenceStr.charCodeAt(i - start);
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| 
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|         // testCode.toLowerCase() for A..Z
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|         if (isUppercaseLetter(testCode)) {
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|             testCode = testCode | 32;
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|         }
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| 
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|         if (testCode !== referenceCode) {
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|             return false;
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|         }
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|     }
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| 
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|     return true;
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| }
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| 
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| function findWhiteSpaceStart(source, offset) {
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|     for (; offset >= 0; offset--) {
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|         if (!isWhiteSpace(source.charCodeAt(offset))) {
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|             break;
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|         }
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|     }
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| 
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|     return offset + 1;
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| }
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| 
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| function findWhiteSpaceEnd(source, offset) {
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|     for (; offset < source.length; offset++) {
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|         if (!isWhiteSpace(source.charCodeAt(offset))) {
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|             break;
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|         }
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|     }
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| 
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|     return offset;
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| }
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| 
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| function findDecimalNumberEnd(source, offset) {
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|     for (; offset < source.length; offset++) {
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|         if (!isDigit(source.charCodeAt(offset))) {
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|             break;
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|         }
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|     }
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| 
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|     return offset;
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| }
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| 
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| // § 4.3.7. Consume an escaped code point
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| function consumeEscaped(source, offset) {
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|     // It assumes that the U+005C REVERSE SOLIDUS (\) has already been consumed and
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|     // that the next input code point has already been verified to be part of a valid escape.
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|     offset += 2;
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| 
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|     // hex digit
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|     if (isHexDigit(getCharCode(source, offset - 1))) {
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|         // Consume as many hex digits as possible, but no more than 5.
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|         // Note that this means 1-6 hex digits have been consumed in total.
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|         for (var maxOffset = Math.min(source.length, offset + 5); offset < maxOffset; offset++) {
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|             if (!isHexDigit(getCharCode(source, offset))) {
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|                 break;
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|             }
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|         }
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| 
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|         // If the next input code point is whitespace, consume it as well.
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|         var code = getCharCode(source, offset);
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|         if (isWhiteSpace(code)) {
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|             offset += getNewlineLength(source, offset, code);
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|         }
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|     }
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| 
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|     return offset;
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| }
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| 
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| // §4.3.11. Consume a name
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| // Note: This algorithm does not do the verification of the first few code points that are necessary
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| // to ensure the returned code points would constitute an <ident-token>. If that is the intended use,
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| // ensure that the stream starts with an identifier before calling this algorithm.
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| function consumeName(source, offset) {
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|     // Let result initially be an empty string.
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|     // Repeatedly consume the next input code point from the stream:
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|     for (; offset < source.length; offset++) {
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|         var code = source.charCodeAt(offset);
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| 
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|         // name code point
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|         if (isName(code)) {
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|             // Append the code point to result.
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|             continue;
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|         }
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| 
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|         // the stream starts with a valid escape
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|         if (isValidEscape(code, getCharCode(source, offset + 1))) {
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|             // Consume an escaped code point. Append the returned code point to result.
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|             offset = consumeEscaped(source, offset) - 1;
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|             continue;
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|         }
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| 
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|         // anything else
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|         // Reconsume the current input code point. Return result.
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|         break;
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|     }
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| 
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|     return offset;
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| }
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| 
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| // §4.3.12. Consume a number
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| function consumeNumber(source, offset) {
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|     var code = source.charCodeAt(offset);
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| 
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|     // 2. If the next input code point is U+002B PLUS SIGN (+) or U+002D HYPHEN-MINUS (-),
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|     // consume it and append it to repr.
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|     if (code === 0x002B || code === 0x002D) {
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|         code = source.charCodeAt(offset += 1);
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|     }
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| 
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|     // 3. While the next input code point is a digit, consume it and append it to repr.
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|     if (isDigit(code)) {
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|         offset = findDecimalNumberEnd(source, offset + 1);
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|         code = source.charCodeAt(offset);
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|     }
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| 
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|     // 4. If the next 2 input code points are U+002E FULL STOP (.) followed by a digit, then:
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|     if (code === 0x002E && isDigit(source.charCodeAt(offset + 1))) {
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|         // 4.1 Consume them.
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|         // 4.2 Append them to repr.
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|         code = source.charCodeAt(offset += 2);
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| 
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|         // 4.3 Set type to "number".
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|         // TODO
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| 
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|         // 4.4 While the next input code point is a digit, consume it and append it to repr.
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| 
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|         offset = findDecimalNumberEnd(source, offset);
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|     }
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| 
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|     // 5. If the next 2 or 3 input code points are U+0045 LATIN CAPITAL LETTER E (E)
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|     // or U+0065 LATIN SMALL LETTER E (e), ... , followed by a digit, then:
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|     if (cmpChar(source, offset, 101 /* e */)) {
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|         var sign = 0;
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|         code = source.charCodeAt(offset + 1);
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| 
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|         // ... optionally followed by U+002D HYPHEN-MINUS (-) or U+002B PLUS SIGN (+) ...
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|         if (code === 0x002D || code === 0x002B) {
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|             sign = 1;
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|             code = source.charCodeAt(offset + 2);
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|         }
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| 
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|         // ... followed by a digit
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|         if (isDigit(code)) {
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|             // 5.1 Consume them.
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|             // 5.2 Append them to repr.
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| 
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|             // 5.3 Set type to "number".
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|             // TODO
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| 
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|             // 5.4 While the next input code point is a digit, consume it and append it to repr.
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|             offset = findDecimalNumberEnd(source, offset + 1 + sign + 1);
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|         }
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|     }
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| 
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|     return offset;
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| }
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| 
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| // § 4.3.14. Consume the remnants of a bad url
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| // ... its sole use is to consume enough of the input stream to reach a recovery point
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| // where normal tokenizing can resume.
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| function consumeBadUrlRemnants(source, offset) {
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|     // Repeatedly consume the next input code point from the stream:
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|     for (; offset < source.length; offset++) {
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|         var code = source.charCodeAt(offset);
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| 
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|         // U+0029 RIGHT PARENTHESIS ())
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|         // EOF
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|         if (code === 0x0029) {
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|             // Return.
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|             offset++;
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|             break;
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|         }
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| 
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|         if (isValidEscape(code, getCharCode(source, offset + 1))) {
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|             // Consume an escaped code point.
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|             // Note: This allows an escaped right parenthesis ("\)") to be encountered
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|             // without ending the <bad-url-token>. This is otherwise identical to
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|             // the "anything else" clause.
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|             offset = consumeEscaped(source, offset);
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|         }
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|     }
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| 
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|     return offset;
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| }
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| 
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| module.exports = {
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|     consumeEscaped: consumeEscaped,
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|     consumeName: consumeName,
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|     consumeNumber: consumeNumber,
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|     consumeBadUrlRemnants: consumeBadUrlRemnants,
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| 
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|     cmpChar: cmpChar,
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|     cmpStr: cmpStr,
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| 
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|     getNewlineLength: getNewlineLength,
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|     findWhiteSpaceStart: findWhiteSpaceStart,
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|     findWhiteSpaceEnd: findWhiteSpaceEnd
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| };
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