extendFinder.php000064400000005261151552411540007703 0ustar00<?php

/**
 * Extend Finder Visitor
 *
 * @package Less
 * @subpackage visitor
 */
class Less_Visitor_extendFinder extends Less_Visitor{

	public $contexts = array();
	public $allExtendsStack;
	public $foundExtends;

	public function __construct(){
		$this->contexts = array();
		$this->allExtendsStack = array(array());
		parent::__construct();
	}

	/**
	 * @param Less_Tree_Ruleset $root
	 */
    public function run($root){
		$root = $this->visitObj($root);
		$root->allExtends =& $this->allExtendsStack[0];
		return $root;
	}

    public function visitRule($ruleNode, &$visitDeeper ){
		$visitDeeper = false;
	}

    public function visitMixinDefinition( $mixinDefinitionNode, &$visitDeeper ){
		$visitDeeper = false;
	}

    public function visitRuleset($rulesetNode){

		if( $rulesetNode->root ){
			return;
		}

		$allSelectorsExtendList = array();

		// get &:extend(.a); rules which apply to all selectors in this ruleset
		if( $rulesetNode->rules ){
			foreach($rulesetNode->rules as $rule){
				if( $rule instanceof Less_Tree_Extend ){
					$allSelectorsExtendList[] = $rule;
					$rulesetNode->extendOnEveryPath = true;
				}
			}
		}


		// now find every selector and apply the extends that apply to all extends
		// and the ones which apply to an individual extend
		foreach($rulesetNode->paths as $selectorPath){
			$selector = end($selectorPath); //$selectorPath[ count($selectorPath)-1];

			$j = 0;
			foreach($selector->extendList as $extend){
				$this->allExtendsStackPush($rulesetNode, $selectorPath, $extend, $j);
			}
			foreach($allSelectorsExtendList as $extend){
				$this->allExtendsStackPush($rulesetNode, $selectorPath, $extend, $j);
			}
		}

		$this->contexts[] = $rulesetNode->selectors;
	}

    public function allExtendsStackPush($rulesetNode, $selectorPath, $extend, &$j){
		$this->foundExtends = true;
		$extend = clone $extend;
		$extend->findSelfSelectors( $selectorPath );
		$extend->ruleset = $rulesetNode;
		if( $j === 0 ){
			$extend->firstExtendOnThisSelectorPath = true;
		}

		$end_key = count($this->allExtendsStack)-1;
		$this->allExtendsStack[$end_key][] = $extend;
		$j++;
	}


    public function visitRulesetOut( $rulesetNode ){
		if( !is_object($rulesetNode) || !$rulesetNode->root ){
			array_pop($this->contexts);
		}
	}

    public function visitMedia( $mediaNode ){
		$mediaNode->allExtends = array();
		$this->allExtendsStack[] =& $mediaNode->allExtends;
	}

    public function visitMediaOut(){
		array_pop($this->allExtendsStack);
	}

    public function visitDirective( $directiveNode ){
		$directiveNode->allExtends = array();
		$this->allExtendsStack[] =& $directiveNode->allExtends;
	}

    public function visitDirectiveOut(){
		array_pop($this->allExtendsStack);
	}
}


import.php000064400000006422151552411540006576 0ustar00<?php

/*
class Less_Visitor_import extends Less_VisitorReplacing{

	public $_visitor;
	public $_importer;
	public $importCount;

	function __construct( $evalEnv ){
		$this->env = $evalEnv;
		$this->importCount = 0;
		parent::__construct();
	}


	function run( $root ){
		$root = $this->visitObj($root);
		$this->isFinished = true;

		//if( $this->importCount === 0) {
		//	$this->_finish();
		//}
	}

	function visitImport($importNode, &$visitDeeper ){
		$importVisitor = $this;
		$inlineCSS = $importNode->options['inline'];

		if( !$importNode->css || $inlineCSS ){
			$evaldImportNode = $importNode->compileForImport($this->env);

			if( $evaldImportNode && (!$evaldImportNode->css || $inlineCSS) ){
				$importNode = $evaldImportNode;
				$this->importCount++;
				$env = clone $this->env;

				if( (isset($importNode->options['multiple']) && $importNode->options['multiple']) ){
					$env->importMultiple = true;
				}

				//get path & uri
				$path_and_uri = null;
				if( is_callable(Less_Parser::$options['import_callback']) ){
					$path_and_uri = call_user_func(Less_Parser::$options['import_callback'],$importNode);
				}

				if( !$path_and_uri ){
					$path_and_uri = $importNode->PathAndUri();
				}

				if( $path_and_uri ){
					list($full_path, $uri) = $path_and_uri;
				}else{
					$full_path = $uri = $importNode->getPath();
				}


				//import once
				if( $importNode->skip( $full_path, $env) ){
					return array();
				}

				if( $importNode->options['inline'] ){
					//todo needs to reference css file not import
					//$contents = new Less_Tree_Anonymous($importNode->root, 0, array('filename'=>$importNode->importedFilename), true );

					Less_Parser::AddParsedFile($full_path);
					$contents = new Less_Tree_Anonymous( file_get_contents($full_path), 0, array(), true );

					if( $importNode->features ){
						return new Less_Tree_Media( array($contents), $importNode->features->value );
					}

					return array( $contents );
				}


				// css ?
				if( $importNode->css ){
					$features = ( $importNode->features ? $importNode->features->compile($env) : null );
					return new Less_Tree_Import( $importNode->compilePath( $env), $features, $importNode->options, $this->index);
				}

				return $importNode->ParseImport( $full_path, $uri, $env );
			}

		}

		$visitDeeper = false;
		return $importNode;
	}


	function visitRule( $ruleNode, &$visitDeeper ){
		$visitDeeper = false;
		return $ruleNode;
	}

	function visitDirective($directiveNode, $visitArgs){
		array_unshift($this->env->frames,$directiveNode);
		return $directiveNode;
	}

	function visitDirectiveOut($directiveNode) {
		array_shift($this->env->frames);
	}

	function visitMixinDefinition($mixinDefinitionNode, $visitArgs) {
		array_unshift($this->env->frames,$mixinDefinitionNode);
		return $mixinDefinitionNode;
	}

	function visitMixinDefinitionOut($mixinDefinitionNode) {
		array_shift($this->env->frames);
	}

	function visitRuleset($rulesetNode, $visitArgs) {
		array_unshift($this->env->frames,$rulesetNode);
		return $rulesetNode;
	}

	function visitRulesetOut($rulesetNode) {
		array_shift($this->env->frames);
	}

	function visitMedia($mediaNode, $visitArgs) {
		array_unshift($this->env->frames, $mediaNode->ruleset);
		return $mediaNode;
	}

	function visitMediaOut($mediaNode) {
		array_shift($this->env->frames);
	}

}
*/


joinSelector.php000064400000003076151552411540007726 0ustar00<?php

/**
 * Join Selector Visitor
 *
 * @package Less
 * @subpackage visitor
 */
class Less_Visitor_joinSelector extends Less_Visitor{

	public $contexts = array( array() );

	/**
	 * @param Less_Tree_Ruleset $root
	 */
	public function run( $root ){
		return $this->visitObj($root);
	}

    public function visitRule( $ruleNode, &$visitDeeper ){
		$visitDeeper = false;
	}

    public function visitMixinDefinition( $mixinDefinitionNode, &$visitDeeper ){
		$visitDeeper = false;
	}

    public function visitRuleset( $rulesetNode ){

		$paths = array();

		if( !$rulesetNode->root ){
			$selectors = array();

			if( $rulesetNode->selectors && $rulesetNode->selectors ){
				foreach($rulesetNode->selectors as $selector){
					if( $selector->getIsOutput() ){
						$selectors[] = $selector;
					}
				}
			}

			if( !$selectors ){
				$rulesetNode->selectors = null;
				$rulesetNode->rules = null;
			}else{
				$context = end($this->contexts); //$context = $this->contexts[ count($this->contexts) - 1];
				$paths = $rulesetNode->joinSelectors( $context, $selectors);
			}

			$rulesetNode->paths = $paths;
		}

		$this->contexts[] = $paths; //different from less.js. Placed after joinSelectors() so that $this->contexts will get correct $paths
	}

    public function visitRulesetOut(){
		array_pop($this->contexts);
	}

    public function visitMedia($mediaNode) {
		$context = end($this->contexts); //$context = $this->contexts[ count($this->contexts) - 1];

		if( !count($context) || (is_object($context[0]) && $context[0]->multiMedia) ){
			$mediaNode->rules[0]->root = true;
		}
	}

}

processExtends.php000064400000037172151552411540010303 0ustar00<?php

/**
 * Process Extends Visitor
 *
 * @package Less
 * @subpackage visitor
 */
class Less_Visitor_processExtends extends Less_Visitor{

	public $allExtendsStack;

	/**
	 * @param Less_Tree_Ruleset $root
	 */
	public function run( $root ){
		$extendFinder = new Less_Visitor_extendFinder();
		$extendFinder->run( $root );
		if( !$extendFinder->foundExtends){
			return $root;
		}

		$root->allExtends = $this->doExtendChaining( $root->allExtends, $root->allExtends);

		$this->allExtendsStack = array();
		$this->allExtendsStack[] = &$root->allExtends;

		return $this->visitObj( $root );
	}

	private function doExtendChaining( $extendsList, $extendsListTarget, $iterationCount = 0){
		//
		// chaining is different from normal extension.. if we extend an extend then we are not just copying, altering and pasting
		// the selector we would do normally, but we are also adding an extend with the same target selector
		// this means this new extend can then go and alter other extends
		//
		// this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
		// this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already processed if
		// we look at each selector at a time, as is done in visitRuleset

		$extendsToAdd = array();


		//loop through comparing every extend with every target extend.
		// a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
		// e.g. .a:extend(.b) {} and .b:extend(.c) {} then the first extend extends the second one
		// and the second is the target.
		// the separation into two lists allows us to process a subset of chains with a bigger set, as is the
		// case when processing media queries
		for( $extendIndex = 0, $extendsList_len = count($extendsList); $extendIndex < $extendsList_len; $extendIndex++ ){
			for( $targetExtendIndex = 0; $targetExtendIndex < count($extendsListTarget); $targetExtendIndex++ ){

				$extend = $extendsList[$extendIndex];
				$targetExtend = $extendsListTarget[$targetExtendIndex];

				// Optimisation: Explicit reference, <https://github.com/wikimedia/less.php/pull/14>
				if( \array_key_exists($targetExtend->object_id, $extend->parent_ids) ){
					// ignore circular references
					continue;
				}

				// find a match in the target extends self selector (the bit before :extend)
				$selectorPath = array( $targetExtend->selfSelectors[0] );
				$matches = $this->findMatch( $extend, $selectorPath);


				if( $matches ){

					// we found a match, so for each self selector..
					foreach($extend->selfSelectors as $selfSelector ){


						// process the extend as usual
						$newSelector = $this->extendSelector( $matches, $selectorPath, $selfSelector);

						// but now we create a new extend from it
						$newExtend = new Less_Tree_Extend( $targetExtend->selector, $targetExtend->option, 0);
						$newExtend->selfSelectors = $newSelector;

						// add the extend onto the list of extends for that selector
						end($newSelector)->extendList = array($newExtend);
						//$newSelector[ count($newSelector)-1]->extendList = array($newExtend);

						// record that we need to add it.
						$extendsToAdd[] = $newExtend;
						$newExtend->ruleset = $targetExtend->ruleset;

						//remember its parents for circular references
						$newExtend->parent_ids = array_merge($newExtend->parent_ids,$targetExtend->parent_ids,$extend->parent_ids);

						// only process the selector once.. if we have :extend(.a,.b) then multiple
						// extends will look at the same selector path, so when extending
						// we know that any others will be duplicates in terms of what is added to the css
						if( $targetExtend->firstExtendOnThisSelectorPath ){
							$newExtend->firstExtendOnThisSelectorPath = true;
							$targetExtend->ruleset->paths[] = $newSelector;
						}
					}
				}
			}
		}

		if( $extendsToAdd ){
			// try to detect circular references to stop a stack overflow.
			// may no longer be needed.			$this->extendChainCount++;
			if( $iterationCount > 100) {

				try{
					$selectorOne = $extendsToAdd[0]->selfSelectors[0]->toCSS();
					$selectorTwo = $extendsToAdd[0]->selector->toCSS();
				}catch(Exception $e){
					$selectorOne = "{unable to calculate}";
					$selectorTwo = "{unable to calculate}";
				}

				throw new Less_Exception_Parser("extend circular reference detected. One of the circular extends is currently:" . $selectorOne . ":extend(" . $selectorTwo . ")");
			}

			// now process the new extends on the existing rules so that we can handle a extending b extending c ectending d extending e...
			$extendsToAdd = $this->doExtendChaining( $extendsToAdd, $extendsListTarget, $iterationCount+1);
		}

		return array_merge($extendsList, $extendsToAdd);
	}


	protected function visitRule( $ruleNode, &$visitDeeper ){
		$visitDeeper = false;
	}

	protected function visitMixinDefinition( $mixinDefinitionNode, &$visitDeeper ){
		$visitDeeper = false;
	}

	protected function visitSelector( $selectorNode, &$visitDeeper ){
		$visitDeeper = false;
	}

	protected function visitRuleset($rulesetNode){


		if( $rulesetNode->root ){
			return;
		}

		$allExtends	= end($this->allExtendsStack);
		$paths_len = count($rulesetNode->paths);

		// look at each selector path in the ruleset, find any extend matches and then copy, find and replace
		foreach($allExtends as $allExtend){
			for($pathIndex = 0; $pathIndex < $paths_len; $pathIndex++ ){

				// extending extends happens initially, before the main pass
				if( isset($rulesetNode->extendOnEveryPath) && $rulesetNode->extendOnEveryPath ){
					continue;
				}

				$selectorPath = $rulesetNode->paths[$pathIndex];

				if( end($selectorPath)->extendList ){
					continue;
				}

				$this->ExtendMatch( $rulesetNode, $allExtend, $selectorPath);

			}
		}
	}


	private function ExtendMatch( $rulesetNode, $extend, $selectorPath ){
		$matches = $this->findMatch($extend, $selectorPath);

		if( $matches ){
			foreach($extend->selfSelectors as $selfSelector ){
				$rulesetNode->paths[] = $this->extendSelector($matches, $selectorPath, $selfSelector);
			}
		}
	}



	private function findMatch($extend, $haystackSelectorPath ){


		if( !$this->HasMatches($extend, $haystackSelectorPath) ){
			return false;
		}


		//
		// look through the haystack selector path to try and find the needle - extend.selector
		// returns an array of selector matches that can then be replaced
		//
		$needleElements = $extend->selector->elements;
		$potentialMatches = array();
		$potentialMatches_len = 0;
		$potentialMatch = null;
		$matches = array();



		// loop through the haystack elements
		$haystack_path_len = count($haystackSelectorPath);
		for($haystackSelectorIndex = 0; $haystackSelectorIndex < $haystack_path_len; $haystackSelectorIndex++ ){
			$hackstackSelector = $haystackSelectorPath[$haystackSelectorIndex];

			$haystack_elements_len = count($hackstackSelector->elements);
			for($hackstackElementIndex = 0; $hackstackElementIndex < $haystack_elements_len; $hackstackElementIndex++ ){

				$haystackElement = $hackstackSelector->elements[$hackstackElementIndex];

				// if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
				if( $extend->allowBefore || ($haystackSelectorIndex === 0 && $hackstackElementIndex === 0) ){
					$potentialMatches[] = array('pathIndex'=> $haystackSelectorIndex, 'index'=> $hackstackElementIndex, 'matched'=> 0, 'initialCombinator'=> $haystackElement->combinator);
					$potentialMatches_len++;
				}

				for($i = 0; $i < $potentialMatches_len; $i++ ){

					$potentialMatch = &$potentialMatches[$i];
					$potentialMatch = $this->PotentialMatch( $potentialMatch, $needleElements, $haystackElement, $hackstackElementIndex );


					// if we are still valid and have finished, test whether we have elements after and whether these are allowed
					if( $potentialMatch && $potentialMatch['matched'] === $extend->selector->elements_len ){
						$potentialMatch['finished'] = true;

						if( !$extend->allowAfter && ($hackstackElementIndex+1 < $haystack_elements_len || $haystackSelectorIndex+1 < $haystack_path_len) ){
							$potentialMatch = null;
						}
					}

					// if null we remove, if not, we are still valid, so either push as a valid match or continue
					if( $potentialMatch ){
						if( $potentialMatch['finished'] ){
							$potentialMatch['length'] = $extend->selector->elements_len;
							$potentialMatch['endPathIndex'] = $haystackSelectorIndex;
							$potentialMatch['endPathElementIndex'] = $hackstackElementIndex + 1; // index after end of match
							$potentialMatches = array(); // we don't allow matches to overlap, so start matching again
							$potentialMatches_len = 0;
							$matches[] = $potentialMatch;
						}
						continue;
					}

					array_splice($potentialMatches, $i, 1);
					$potentialMatches_len--;
					$i--;
				}
			}
		}

		return $matches;
	}


	// Before going through all the nested loops, lets check to see if a match is possible
	// Reduces Bootstrap 3.1 compile time from ~6.5s to ~5.6s
	private function HasMatches($extend, $haystackSelectorPath){

		if( !$extend->selector->cacheable ){
			return true;
		}

		$first_el = $extend->selector->_oelements[0];

		foreach($haystackSelectorPath as $hackstackSelector){
			if( !$hackstackSelector->cacheable ){
				return true;
			}

			// Optimisation: Explicit reference, <https://github.com/wikimedia/less.php/pull/14>
			if( \array_key_exists($first_el, $hackstackSelector->_oelements_assoc) ){
				return true;
			}
		}

		return false;
	}


	/**
	 * @param integer $hackstackElementIndex
	 */
	private function PotentialMatch( $potentialMatch, $needleElements, $haystackElement, $hackstackElementIndex ){


		if( $potentialMatch['matched'] > 0 ){

			// selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
			// then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to work out
			// what the resulting combinator will be
			$targetCombinator = $haystackElement->combinator;
			if( $targetCombinator === '' && $hackstackElementIndex === 0 ){
				$targetCombinator = ' ';
			}

			if( $needleElements[ $potentialMatch['matched'] ]->combinator !== $targetCombinator ){
				return null;
			}
		}

		// if we don't match, null our match to indicate failure
		if( !$this->isElementValuesEqual( $needleElements[$potentialMatch['matched'] ]->value, $haystackElement->value) ){
			return null;
		}

		$potentialMatch['finished'] = false;
		$potentialMatch['matched']++;

		return $potentialMatch;
	}


	private function isElementValuesEqual( $elementValue1, $elementValue2 ){

		if( $elementValue1 === $elementValue2 ){
			return true;
		}

		if( is_string($elementValue1) || is_string($elementValue2) ) {
			return false;
		}

		if( $elementValue1 instanceof Less_Tree_Attribute ){
			return $this->isAttributeValuesEqual( $elementValue1, $elementValue2 );
		}

		$elementValue1 = $elementValue1->value;
		if( $elementValue1 instanceof Less_Tree_Selector ){
			return $this->isSelectorValuesEqual( $elementValue1, $elementValue2 );
		}

		return false;
	}


	/**
	 * @param Less_Tree_Selector $elementValue1
	 */
	private function isSelectorValuesEqual( $elementValue1, $elementValue2 ){

		$elementValue2 = $elementValue2->value;
		if( !($elementValue2 instanceof Less_Tree_Selector) || $elementValue1->elements_len !== $elementValue2->elements_len ){
			return false;
		}

		for( $i = 0; $i < $elementValue1->elements_len; $i++ ){

			if( $elementValue1->elements[$i]->combinator !== $elementValue2->elements[$i]->combinator ){
				if( $i !== 0 || ($elementValue1->elements[$i]->combinator || ' ') !== ($elementValue2->elements[$i]->combinator || ' ') ){
					return false;
				}
			}

			if( !$this->isElementValuesEqual($elementValue1->elements[$i]->value, $elementValue2->elements[$i]->value) ){
				return false;
			}
		}

		return true;
	}


	/**
	 * @param Less_Tree_Attribute $elementValue1
	 */
	private function isAttributeValuesEqual( $elementValue1, $elementValue2 ){

		if( $elementValue1->op !== $elementValue2->op || $elementValue1->key !== $elementValue2->key ){
			return false;
		}

		if( !$elementValue1->value || !$elementValue2->value ){
			if( $elementValue1->value || $elementValue2->value ) {
				return false;
			}
			return true;
		}

		$elementValue1 = ($elementValue1->value->value ? $elementValue1->value->value : $elementValue1->value );
		$elementValue2 = ($elementValue2->value->value ? $elementValue2->value->value : $elementValue2->value );

		return $elementValue1 === $elementValue2;
	}


	private function extendSelector($matches, $selectorPath, $replacementSelector){

		//for a set of matches, replace each match with the replacement selector

		$currentSelectorPathIndex = 0;
		$currentSelectorPathElementIndex = 0;
		$path = array();
		$selectorPath_len = count($selectorPath);

		for($matchIndex = 0, $matches_len = count($matches); $matchIndex < $matches_len; $matchIndex++ ){


			$match = $matches[$matchIndex];
			$selector = $selectorPath[ $match['pathIndex'] ];

			$firstElement = new Less_Tree_Element(
				$match['initialCombinator'],
				$replacementSelector->elements[0]->value,
				$replacementSelector->elements[0]->index,
				$replacementSelector->elements[0]->currentFileInfo
			);

			if( $match['pathIndex'] > $currentSelectorPathIndex && $currentSelectorPathElementIndex > 0 ){
				$last_path = end($path);
				$last_path->elements = array_merge( $last_path->elements, array_slice( $selectorPath[$currentSelectorPathIndex]->elements, $currentSelectorPathElementIndex));
				$currentSelectorPathElementIndex = 0;
				$currentSelectorPathIndex++;
			}

			$newElements = array_merge(
				array_slice($selector->elements, $currentSelectorPathElementIndex, ($match['index'] - $currentSelectorPathElementIndex) ) // last parameter of array_slice is different than the last parameter of javascript's slice
				, array($firstElement)
				, array_slice($replacementSelector->elements,1)
				);

			if( $currentSelectorPathIndex === $match['pathIndex'] && $matchIndex > 0 ){
				$last_key = count($path)-1;
				$path[$last_key]->elements = array_merge($path[$last_key]->elements,$newElements);
			}else{
				$path = array_merge( $path, array_slice( $selectorPath, $currentSelectorPathIndex, $match['pathIndex'] ));
				$path[] = new Less_Tree_Selector( $newElements );
			}

			$currentSelectorPathIndex = $match['endPathIndex'];
			$currentSelectorPathElementIndex = $match['endPathElementIndex'];
			if( $currentSelectorPathElementIndex >= count($selectorPath[$currentSelectorPathIndex]->elements) ){
				$currentSelectorPathElementIndex = 0;
				$currentSelectorPathIndex++;
			}
		}

		if( $currentSelectorPathIndex < $selectorPath_len && $currentSelectorPathElementIndex > 0 ){
			$last_path = end($path);
			$last_path->elements = array_merge( $last_path->elements, array_slice($selectorPath[$currentSelectorPathIndex]->elements, $currentSelectorPathElementIndex));
			$currentSelectorPathIndex++;
		}

		$slice_len = $selectorPath_len - $currentSelectorPathIndex;
		$path = array_merge($path, array_slice($selectorPath, $currentSelectorPathIndex, $slice_len));

		return $path;
	}


	protected function visitMedia( $mediaNode ){
		$newAllExtends = array_merge( $mediaNode->allExtends, end($this->allExtendsStack) );
		$this->allExtendsStack[] = $this->doExtendChaining($newAllExtends, $mediaNode->allExtends);
	}

	protected function visitMediaOut(){
		array_pop( $this->allExtendsStack );
	}

	protected function visitDirective( $directiveNode ){
		$newAllExtends = array_merge( $directiveNode->allExtends, end($this->allExtendsStack) );
		$this->allExtendsStack[] = $this->doExtendChaining($newAllExtends, $directiveNode->allExtends);
	}

	protected function visitDirectiveOut(){
		array_pop($this->allExtendsStack);
	}

}
toCSS.php000064400000015013151552411540006253 0ustar00<?php

/**
 * toCSS Visitor
 *
 * @package Less
 * @subpackage visitor
 */
class Less_Visitor_toCSS extends Less_VisitorReplacing{

	private $charset;

	public function __construct(){
		parent::__construct();
	}

	/**
	 * @param Less_Tree_Ruleset $root
	 */
	public function run( $root ){
		return $this->visitObj($root);
	}

	public function visitRule( $ruleNode ){
		if( $ruleNode->variable ){
			return array();
		}
		return $ruleNode;
	}

	public function visitMixinDefinition($mixinNode){
		// mixin definitions do not get eval'd - this means they keep state
		// so we have to clear that state here so it isn't used if toCSS is called twice
		$mixinNode->frames = array();
		return array();
	}

	public function visitExtend(){
		return array();
	}

	public function visitComment( $commentNode ){
		if( $commentNode->isSilent() ){
			return array();
		}
		return $commentNode;
	}

	public function visitMedia( $mediaNode, &$visitDeeper ){
		$mediaNode->accept($this);
		$visitDeeper = false;

		if( !$mediaNode->rules ){
			return array();
		}
		return $mediaNode;
	}

	public function visitDirective( $directiveNode ){
		if( isset($directiveNode->currentFileInfo['reference']) && (!property_exists($directiveNode,'isReferenced') || !$directiveNode->isReferenced) ){
			return array();
		}
		if( $directiveNode->name === '@charset' ){
			// Only output the debug info together with subsequent @charset definitions
			// a comment (or @media statement) before the actual @charset directive would
			// be considered illegal css as it has to be on the first line
			if( isset($this->charset) && $this->charset ){

				//if( $directiveNode->debugInfo ){
				//	$comment = new Less_Tree_Comment('/* ' . str_replace("\n",'',$directiveNode->toCSS())." */\n");
				//	$comment->debugInfo = $directiveNode->debugInfo;
				//	return $this->visit($comment);
				//}


				return array();
			}
			$this->charset = true;
		}
		return $directiveNode;
	}

	public function checkPropertiesInRoot( $rulesetNode ){

		if( !$rulesetNode->firstRoot ){
			return;
		}

		foreach($rulesetNode->rules as $ruleNode){
			if( $ruleNode instanceof Less_Tree_Rule && !$ruleNode->variable ){
				$msg = "properties must be inside selector blocks, they cannot be in the root. Index ".$ruleNode->index.($ruleNode->currentFileInfo ? (' Filename: '.$ruleNode->currentFileInfo['filename']) : null);
				throw new Less_Exception_Compiler($msg);
			}
		}
	}


	public function visitRuleset( $rulesetNode, &$visitDeeper ){

		$visitDeeper = false;

		$this->checkPropertiesInRoot( $rulesetNode );

		if( $rulesetNode->root ){
			return $this->visitRulesetRoot( $rulesetNode );
		}

		$rulesets = array();
		$rulesetNode->paths = $this->visitRulesetPaths($rulesetNode);


		// Compile rules and rulesets
		$nodeRuleCnt = $rulesetNode->rules?count($rulesetNode->rules):0;
		for( $i = 0; $i < $nodeRuleCnt; ){
			$rule = $rulesetNode->rules[$i];

			if( property_exists($rule,'rules') ){
				// visit because we are moving them out from being a child
				$rulesets[] = $this->visitObj($rule);
				array_splice($rulesetNode->rules,$i,1);
				$nodeRuleCnt--;
				continue;
			}
			$i++;
		}


		// accept the visitor to remove rules and refactor itself
		// then we can decide now whether we want it or not
		if( $nodeRuleCnt > 0 ){
			$rulesetNode->accept($this);

			if( $rulesetNode->rules ){

				if( count($rulesetNode->rules) >  1 ){
					$this->_mergeRules( $rulesetNode->rules );
					$this->_removeDuplicateRules( $rulesetNode->rules );
				}

				// now decide whether we keep the ruleset
				if( $rulesetNode->paths ){
					//array_unshift($rulesets, $rulesetNode);
					array_splice($rulesets,0,0,array($rulesetNode));
				}
			}

		}


		if( count($rulesets) === 1 ){
			return $rulesets[0];
		}
		return $rulesets;
	}


	/**
	 * Helper function for visitiRuleset
	 *
	 * return array|Less_Tree_Ruleset
	 */
	private function visitRulesetRoot( $rulesetNode ){
		$rulesetNode->accept( $this );
		if( $rulesetNode->firstRoot || $rulesetNode->rules ){
			return $rulesetNode;
		}
		return array();
	}


	/**
	 * Helper function for visitRuleset()
	 *
	 * @return array
	 */
	private function visitRulesetPaths($rulesetNode){

		$paths = array();
		foreach($rulesetNode->paths as $p){
			if( $p[0]->elements[0]->combinator === ' ' ){
				$p[0]->elements[0]->combinator = '';
			}

			foreach($p as $pi){
				if( $pi->getIsReferenced() && $pi->getIsOutput() ){
					$paths[] = $p;
					break;
				}
			}
		}

		return $paths;
	}

	protected function _removeDuplicateRules( &$rules ){
		// remove duplicates
		$ruleCache = array();
		for( $i = count($rules)-1; $i >= 0 ; $i-- ){
			$rule = $rules[$i];
			if( $rule instanceof Less_Tree_Rule || $rule instanceof Less_Tree_NameValue ){

				if( !isset($ruleCache[$rule->name]) ){
					$ruleCache[$rule->name] = $rule;
				}else{
					$ruleList =& $ruleCache[$rule->name];

					if( $ruleList instanceof Less_Tree_Rule || $ruleList instanceof Less_Tree_NameValue ){
						$ruleList = $ruleCache[$rule->name] = array( $ruleCache[$rule->name]->toCSS() );
					}

					$ruleCSS = $rule->toCSS();
					if( array_search($ruleCSS,$ruleList) !== false ){
						array_splice($rules,$i,1);
					}else{
						$ruleList[] = $ruleCSS;
					}
				}
			}
		}
	}

	protected function _mergeRules( &$rules ){
		$groups = array();

		//obj($rules);

		$rules_len = count($rules);
		for( $i = 0; $i < $rules_len; $i++ ){
			$rule = $rules[$i];

			if( ($rule instanceof Less_Tree_Rule) && $rule->merge ){

				$key = $rule->name;
				if( $rule->important ){
					$key .= ',!';
				}

				if( !isset($groups[$key]) ){
					$groups[$key] = array();
				}else{
					array_splice($rules, $i--, 1);
					$rules_len--;
				}

				$groups[$key][] = $rule;
			}
		}


		foreach($groups as $parts){

			if( count($parts) > 1 ){
				$rule = $parts[0];
				$spacedGroups = array();
				$lastSpacedGroup = array();
				$parts_mapped = array();
				foreach($parts as $p){
					if( $p->merge === '+' ){
						if( $lastSpacedGroup ){
							$spacedGroups[] = self::toExpression($lastSpacedGroup);
						}
						$lastSpacedGroup = array();
					}
					$lastSpacedGroup[] = $p;
				}

				$spacedGroups[] = self::toExpression($lastSpacedGroup);
				$rule->value = self::toValue($spacedGroups);
			}
		}

	}

	public static function toExpression($values){
		$mapped = array();
		foreach($values as $p){
			$mapped[] = $p->value;
		}
		return new Less_Tree_Expression( $mapped );
	}

	public static function toValue($values){
		//return new Less_Tree_Value($values); ??

		$mapped = array();
		foreach($values as $p){
			$mapped[] = $p;
		}
		return new Less_Tree_Value($mapped);
	}
}