<?php
function __autoload($class_name) {
	    require_once strtolower($class_name).'.lib.php';
}

abstract class Container {
	var $sID;
	var $aAttributes;
	var $aContents;
	function __construct($id=null,$attributes=array(),$contents=array()) {
		$this->sID = $id;
		if (is_array($attributes)) {
			$this->aAttributes = $attributes;
		}
		if (is_array($contents))
			$this->aContents = $contents;
		else
			$this->add($contents);
	}
    function __get($nm) {
        if (isset($this->aAttributes[$nm])) {
            $r = $this->aAttributes[$nm];
            return $r;
        }
    }
    function __set($nm, $val) {
	//	if (isset($this->aAttributes[$nm])) {
			$this->aAttributes[$nm] = $val;
	//	}
    }
    function __isset($nm) {
        return isset($this->aAttributes[$nm]);
    }
    function __unset($nm) {
        unset($this->aAttributes[$nm]);
    }

	function add($obj) { $this->aContents[] = $obj; }
	function set($obj) { $this->aContents = array($obj); }
	function get_id() { return $this->sID; }
	function has_id() { return !is_null($this->sID); }
	function has_attributes() { return count($this->aAttributes); }
	function get_attributes() { return $this->aAttributes; }
	function get_contents() { return $this->aContents; }

	protected function paint_head() {
		if ($this->has_id()) {
			if ($this->has_attributes()) {
				return sprintf("<%s %s>", strtolower($this->get_id()), $this->paint_attributes());
			} else {
				return sprintf("<%s>", strtolower($this->get_id()));
			}
		}
	}
	protected function paint_attributes() {
		$r = array();
		foreach($this->get_attributes() as $k=>$v) {
			$k = strtolower($k);
			if (is_string($v)) {
				$r[] = "$k=\"$v\"";
			} elseif (is_object($v)) {
				$r[] = "$k=\"".$v->__toString()."\"";
			}
		}
		return implode(' ',$r);
	}
	protected function paint_foot() {
		if ($this->has_id())
			return sprintf("</%s>", strtolower($this->get_id()));
	}
	protected function paint_contents($split='') {
		$r = array();
		foreach($this->get_contents() as $item) {
			if (is_string($item) && is_callable($item)) {
				$args = func_get_args();
				$r[] = ''.call_user_func($item,$args);
			} elseif (is_object($item)) {
				$r[] = ''.$item->__toString();
			} elseif (is_string($item)) {
				$r[] = ''.$item;
			}
		}
		return implode($split,$r);
	}
	function __toString() {
		return $this->paint_head().$this->paint_contents().$this->paint_foot();
	}
}

class Entity extends Container {}