<?php /* SVN FILE: $Id: SassIfNode.php 118 2010-09-21 09:45:11Z chris.l.yates@gmail.com $ */ /**

* SassIfNode class file.
* @author                      Chris Yates <chris.l.yates@gmail.com>
* @copyright   Copyright (c) 2010 PBM Web Development
* @license                     http://phamlp.googlecode.com/files/license.txt
* @package                     PHamlP
* @subpackage  Sass.tree
*/

/**

* SassIfNode class.
* Represents Sass If, Else If and Else statements.
* Else If and Else statement nodes are chained below the If statement node.
* @package                     PHamlP
* @subpackage  Sass.tree
*/

class SassIfNode extends SassNode {

const MATCH_IF = '/^@if\s+(.+)$/i';
const MATCH_ELSE = '/@else(\s+if\s+(.+))?/i';
const IF_EXPRESSION = 1;
const ELSE_IF = 1;
const ELSE_EXPRESSION = 2;
/**
 * @var SassIfNode the next else node.
 */
private $else;
/**
 * @var string expression to evaluate
 */
private $expression;

/**
 * SassIfNode constructor.
 * @param object source token
 * @param boolean true for an "if" node, false for an "else if | else" node
 * @return SassIfNode
 */
public function __construct($token, $if=true) {
        parent::__construct($token);
        if ($if) {
                preg_match(self::MATCH_IF, $token->source, $matches);
                $this->expression = $matches[SassIfNode::IF_EXPRESSION];
        }
        else {
                preg_match(self::MATCH_ELSE, $token->source, $matches);
                $this->expression = (sizeof($matches)==1 ? null : $matches[SassIfNode::ELSE_EXPRESSION]);
        }
}

/**
 * Adds an "else" statement to this node.
 * @param SassIfNode "else" statement node to add
 * @return SassIfNode this node
 */
public function addElse($node) {
  if (is_null($this->else)) {
        $node->parent   = $this->parent;
        $node->root             = $this->root;
                $this->else             = $node;
  }
  else {
                $this->else->addElse($node);
  }
  return $this;
}

/**
 * Parse this node.
 * @param SassContext the context in which this node is parsed
 * @return array parsed child nodes
 */
public function parse($context) {
        if ($this->isElse() || $this->evaluate($this->expression, $context)->toBoolean()) {
                $children = $this->parseChildren($context);
        }
        elseif (!empty($this->else)) {
                $children = $this->else->parse($context);
        }
        else {
                $children = array();
        }
        return $children;
}

/**
 * Returns a value indicating if this node is an "else" node.
 * @return true if this node is an "else" node, false if this node is an "if"
 * or "else if" node
 */
private function isElse() {
  return empty($this->expression);
}

}