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231 lines
6.6 KiB
231 lines
6.6 KiB
'use strict'; |
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const EOF = 0; |
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// https://drafts.csswg.org/css-syntax-3/ |
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// § 4.2. Definitions |
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// digit |
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// A code point between U+0030 DIGIT ZERO (0) and U+0039 DIGIT NINE (9). |
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function isDigit(code) { |
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return code >= 0x0030 && code <= 0x0039; |
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} |
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// hex digit |
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// A digit, or a code point between U+0041 LATIN CAPITAL LETTER A (A) and U+0046 LATIN CAPITAL LETTER F (F), |
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// or a code point between U+0061 LATIN SMALL LETTER A (a) and U+0066 LATIN SMALL LETTER F (f). |
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function isHexDigit(code) { |
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return ( |
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isDigit(code) || // 0 .. 9 |
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(code >= 0x0041 && code <= 0x0046) || // A .. F |
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(code >= 0x0061 && code <= 0x0066) // a .. f |
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); |
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} |
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// uppercase letter |
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// A code point between U+0041 LATIN CAPITAL LETTER A (A) and U+005A LATIN CAPITAL LETTER Z (Z). |
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function isUppercaseLetter(code) { |
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return code >= 0x0041 && code <= 0x005A; |
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} |
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// lowercase letter |
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// A code point between U+0061 LATIN SMALL LETTER A (a) and U+007A LATIN SMALL LETTER Z (z). |
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function isLowercaseLetter(code) { |
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return code >= 0x0061 && code <= 0x007A; |
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} |
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// letter |
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// An uppercase letter or a lowercase letter. |
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function isLetter(code) { |
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return isUppercaseLetter(code) || isLowercaseLetter(code); |
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} |
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// non-ASCII code point |
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// A code point with a value equal to or greater than U+0080 <control>. |
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function isNonAscii(code) { |
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return code >= 0x0080; |
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} |
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// name-start code point |
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// A letter, a non-ASCII code point, or U+005F LOW LINE (_). |
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function isNameStart(code) { |
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return isLetter(code) || isNonAscii(code) || code === 0x005F; |
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} |
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// name code point |
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// A name-start code point, a digit, or U+002D HYPHEN-MINUS (-). |
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function isName(code) { |
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return isNameStart(code) || isDigit(code) || code === 0x002D; |
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} |
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// non-printable code point |
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// A code point between U+0000 NULL and U+0008 BACKSPACE, or U+000B LINE TABULATION, |
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// or a code point between U+000E SHIFT OUT and U+001F INFORMATION SEPARATOR ONE, or U+007F DELETE. |
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function isNonPrintable(code) { |
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return ( |
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(code >= 0x0000 && code <= 0x0008) || |
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(code === 0x000B) || |
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(code >= 0x000E && code <= 0x001F) || |
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(code === 0x007F) |
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); |
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} |
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// newline |
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// U+000A LINE FEED. Note that U+000D CARRIAGE RETURN and U+000C FORM FEED are not included in this definition, |
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// as they are converted to U+000A LINE FEED during preprocessing. |
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// TODO: we doesn't do a preprocessing, so check a code point for U+000D CARRIAGE RETURN and U+000C FORM FEED |
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function isNewline(code) { |
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return code === 0x000A || code === 0x000D || code === 0x000C; |
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} |
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// whitespace |
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// A newline, U+0009 CHARACTER TABULATION, or U+0020 SPACE. |
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function isWhiteSpace(code) { |
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return isNewline(code) || code === 0x0020 || code === 0x0009; |
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} |
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// § 4.3.8. Check if two code points are a valid escape |
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function isValidEscape(first, second) { |
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// If the first code point is not U+005C REVERSE SOLIDUS (\), return false. |
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if (first !== 0x005C) { |
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return false; |
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} |
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// Otherwise, if the second code point is a newline or EOF, return false. |
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if (isNewline(second) || second === EOF) { |
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return false; |
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} |
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// Otherwise, return true. |
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return true; |
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} |
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// § 4.3.9. Check if three code points would start an identifier |
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function isIdentifierStart(first, second, third) { |
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// Look at the first code point: |
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// U+002D HYPHEN-MINUS |
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if (first === 0x002D) { |
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// If the second code point is a name-start code point or a U+002D HYPHEN-MINUS, |
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// or the second and third code points are a valid escape, return true. Otherwise, return false. |
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return ( |
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isNameStart(second) || |
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second === 0x002D || |
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isValidEscape(second, third) |
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); |
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} |
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// name-start code point |
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if (isNameStart(first)) { |
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// Return true. |
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return true; |
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} |
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// U+005C REVERSE SOLIDUS (\) |
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if (first === 0x005C) { |
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// If the first and second code points are a valid escape, return true. Otherwise, return false. |
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return isValidEscape(first, second); |
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} |
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// anything else |
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// Return false. |
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return false; |
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} |
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// § 4.3.10. Check if three code points would start a number |
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function isNumberStart(first, second, third) { |
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// Look at the first code point: |
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// U+002B PLUS SIGN (+) |
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// U+002D HYPHEN-MINUS (-) |
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if (first === 0x002B || first === 0x002D) { |
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// If the second code point is a digit, return true. |
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if (isDigit(second)) { |
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return 2; |
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} |
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// Otherwise, if the second code point is a U+002E FULL STOP (.) |
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// and the third code point is a digit, return true. |
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// Otherwise, return false. |
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return second === 0x002E && isDigit(third) ? 3 : 0; |
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} |
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// U+002E FULL STOP (.) |
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if (first === 0x002E) { |
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// If the second code point is a digit, return true. Otherwise, return false. |
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return isDigit(second) ? 2 : 0; |
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} |
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// digit |
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if (isDigit(first)) { |
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// Return true. |
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return 1; |
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} |
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// anything else |
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// Return false. |
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return 0; |
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} |
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// |
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// Misc |
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// |
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// detect BOM (https://en.wikipedia.org/wiki/Byte_order_mark) |
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function isBOM(code) { |
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// UTF-16BE |
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if (code === 0xFEFF) { |
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return 1; |
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} |
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// UTF-16LE |
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if (code === 0xFFFE) { |
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return 1; |
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} |
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return 0; |
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} |
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// Fast code category |
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// Only ASCII code points has a special meaning, that's why we define a maps for 0..127 codes only |
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const CATEGORY = new Array(0x80); |
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const EofCategory = 0x80; |
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const WhiteSpaceCategory = 0x82; |
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const DigitCategory = 0x83; |
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const NameStartCategory = 0x84; |
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const NonPrintableCategory = 0x85; |
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for (let i = 0; i < CATEGORY.length; i++) { |
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CATEGORY[i] = |
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isWhiteSpace(i) && WhiteSpaceCategory || |
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isDigit(i) && DigitCategory || |
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isNameStart(i) && NameStartCategory || |
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isNonPrintable(i) && NonPrintableCategory || |
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i || EofCategory; |
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} |
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function charCodeCategory(code) { |
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return code < 0x80 ? CATEGORY[code] : NameStartCategory; |
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} |
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exports.DigitCategory = DigitCategory; |
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exports.EofCategory = EofCategory; |
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exports.NameStartCategory = NameStartCategory; |
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exports.NonPrintableCategory = NonPrintableCategory; |
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exports.WhiteSpaceCategory = WhiteSpaceCategory; |
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exports.charCodeCategory = charCodeCategory; |
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exports.isBOM = isBOM; |
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exports.isDigit = isDigit; |
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exports.isHexDigit = isHexDigit; |
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exports.isIdentifierStart = isIdentifierStart; |
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exports.isLetter = isLetter; |
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exports.isLowercaseLetter = isLowercaseLetter; |
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exports.isName = isName; |
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exports.isNameStart = isNameStart; |
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exports.isNewline = isNewline; |
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exports.isNonAscii = isNonAscii; |
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exports.isNonPrintable = isNonPrintable; |
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exports.isNumberStart = isNumberStart; |
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exports.isUppercaseLetter = isUppercaseLetter; |
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exports.isValidEscape = isValidEscape; |
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exports.isWhiteSpace = isWhiteSpace;
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