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259 lines
6.8 KiB
259 lines
6.8 KiB
var Marker = require('../../tokenizer/marker');
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var split = require('../../utils/split');
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var DEEP_SELECTOR_PATTERN = /\/deep\//;
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var DOUBLE_COLON_PATTERN = /^::/;
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var NOT_PSEUDO = ':not';
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var PSEUDO_CLASSES_WITH_ARGUMENTS = [
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':dir',
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':lang',
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':not',
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':nth-child',
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':nth-last-child',
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':nth-last-of-type',
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':nth-of-type'
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];
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var RELATION_PATTERN = /[>\+~]/;
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var UNMIXABLE_PSEUDO_CLASSES = [
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':after',
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':before',
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':first-letter',
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':first-line',
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':lang'
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];
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var UNMIXABLE_PSEUDO_ELEMENTS = [
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'::after',
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'::before',
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'::first-letter',
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'::first-line'
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];
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var Level = {
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DOUBLE_QUOTE: 'double-quote',
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SINGLE_QUOTE: 'single-quote',
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ROOT: 'root'
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};
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function isMergeable(selector, mergeablePseudoClasses, mergeablePseudoElements, multiplePseudoMerging) {
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var singleSelectors = split(selector, Marker.COMMA);
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var singleSelector;
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var i, l;
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for (i = 0, l = singleSelectors.length; i < l; i++) {
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singleSelector = singleSelectors[i];
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if (singleSelector.length === 0 ||
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isDeepSelector(singleSelector) ||
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(singleSelector.indexOf(Marker.COLON) > -1 && !areMergeable(singleSelector, extractPseudoFrom(singleSelector), mergeablePseudoClasses, mergeablePseudoElements, multiplePseudoMerging))) {
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return false;
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}
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}
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return true;
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}
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function isDeepSelector(selector) {
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return DEEP_SELECTOR_PATTERN.test(selector);
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}
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function extractPseudoFrom(selector) {
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var list = [];
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var character;
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var buffer = [];
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var level = Level.ROOT;
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var roundBracketLevel = 0;
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var isQuoted;
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var isEscaped;
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var isPseudo = false;
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var isRelation;
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var wasColon = false;
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var index;
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var len;
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for (index = 0, len = selector.length; index < len; index++) {
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character = selector[index];
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isRelation = !isEscaped && RELATION_PATTERN.test(character);
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isQuoted = level == Level.DOUBLE_QUOTE || level == Level.SINGLE_QUOTE;
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if (isEscaped) {
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buffer.push(character);
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} else if (character == Marker.DOUBLE_QUOTE && level == Level.ROOT) {
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buffer.push(character);
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level = Level.DOUBLE_QUOTE;
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} else if (character == Marker.DOUBLE_QUOTE && level == Level.DOUBLE_QUOTE) {
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buffer.push(character);
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level = Level.ROOT;
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} else if (character == Marker.SINGLE_QUOTE && level == Level.ROOT) {
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buffer.push(character);
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level = Level.SINGLE_QUOTE;
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} else if (character == Marker.SINGLE_QUOTE && level == Level.SINGLE_QUOTE) {
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buffer.push(character);
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level = Level.ROOT;
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} else if (isQuoted) {
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buffer.push(character);
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} else if (character == Marker.OPEN_ROUND_BRACKET) {
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buffer.push(character);
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roundBracketLevel++;
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} else if (character == Marker.CLOSE_ROUND_BRACKET && roundBracketLevel == 1 && isPseudo) {
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buffer.push(character);
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list.push(buffer.join(''));
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roundBracketLevel--;
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buffer = [];
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isPseudo = false;
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} else if (character == Marker.CLOSE_ROUND_BRACKET) {
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buffer.push(character);
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roundBracketLevel--;
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} else if (character == Marker.COLON && roundBracketLevel === 0 && isPseudo && !wasColon) {
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list.push(buffer.join(''));
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buffer = [];
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buffer.push(character);
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} else if (character == Marker.COLON && roundBracketLevel === 0 && !wasColon) {
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buffer = [];
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buffer.push(character);
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isPseudo = true;
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} else if (character == Marker.SPACE && roundBracketLevel === 0 && isPseudo) {
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list.push(buffer.join(''));
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buffer = [];
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isPseudo = false;
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} else if (isRelation && roundBracketLevel === 0 && isPseudo) {
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list.push(buffer.join(''));
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buffer = [];
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isPseudo = false;
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} else {
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buffer.push(character);
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}
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isEscaped = character == Marker.BACK_SLASH;
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wasColon = character == Marker.COLON;
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}
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if (buffer.length > 0 && isPseudo) {
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list.push(buffer.join(''));
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}
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return list;
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}
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function areMergeable(selector, matches, mergeablePseudoClasses, mergeablePseudoElements, multiplePseudoMerging) {
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return areAllowed(matches, mergeablePseudoClasses, mergeablePseudoElements) &&
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needArguments(matches) &&
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(matches.length < 2 || !someIncorrectlyChained(selector, matches)) &&
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(matches.length < 2 || multiplePseudoMerging && allMixable(matches));
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}
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function areAllowed(matches, mergeablePseudoClasses, mergeablePseudoElements) {
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var match;
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var name;
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var i, l;
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for (i = 0, l = matches.length; i < l; i++) {
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match = matches[i];
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name = match.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
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match.substring(0, match.indexOf(Marker.OPEN_ROUND_BRACKET)) :
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match;
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if (mergeablePseudoClasses.indexOf(name) === -1 && mergeablePseudoElements.indexOf(name) === -1) {
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return false;
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}
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}
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return true;
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}
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function needArguments(matches) {
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var match;
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var name;
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var bracketOpensAt;
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var hasArguments;
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var i, l;
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for (i = 0, l = matches.length; i < l; i++) {
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match = matches[i];
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bracketOpensAt = match.indexOf(Marker.OPEN_ROUND_BRACKET);
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hasArguments = bracketOpensAt > -1;
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name = hasArguments ?
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match.substring(0, bracketOpensAt) :
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match;
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if (hasArguments && PSEUDO_CLASSES_WITH_ARGUMENTS.indexOf(name) == -1) {
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return false;
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}
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if (!hasArguments && PSEUDO_CLASSES_WITH_ARGUMENTS.indexOf(name) > -1) {
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return false;
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}
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}
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return true;
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}
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function someIncorrectlyChained(selector, matches) {
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var positionInSelector = 0;
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var match;
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var matchAt;
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var nextMatch;
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var nextMatchAt;
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var name;
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var nextName;
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var areChained;
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var i, l;
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for (i = 0, l = matches.length; i < l; i++) {
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match = matches[i];
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nextMatch = matches[i + 1];
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if (!nextMatch) {
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break;
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}
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matchAt = selector.indexOf(match, positionInSelector);
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nextMatchAt = selector.indexOf(match, matchAt + 1);
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positionInSelector = nextMatchAt;
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areChained = matchAt + match.length == nextMatchAt;
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if (areChained) {
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name = match.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
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match.substring(0, match.indexOf(Marker.OPEN_ROUND_BRACKET)) :
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match;
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nextName = nextMatch.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
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nextMatch.substring(0, nextMatch.indexOf(Marker.OPEN_ROUND_BRACKET)) :
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nextMatch;
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if (name != NOT_PSEUDO || nextName != NOT_PSEUDO) {
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return true;
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}
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}
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}
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return false;
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}
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function allMixable(matches) {
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var unmixableMatches = 0;
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var match;
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var i, l;
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for (i = 0, l = matches.length; i < l; i++) {
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match = matches[i];
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if (isPseudoElement(match)) {
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unmixableMatches += UNMIXABLE_PSEUDO_ELEMENTS.indexOf(match) > -1 ? 1 : 0;
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} else {
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unmixableMatches += UNMIXABLE_PSEUDO_CLASSES.indexOf(match) > -1 ? 1 : 0;
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}
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if (unmixableMatches > 1) {
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return false;
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}
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}
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return true;
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}
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function isPseudoElement(pseudo) {
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return DOUBLE_COLON_PATTERN.test(pseudo);
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}
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module.exports = isMergeable;
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