Cannot access empty property

PHPeaURL

I have the following class which simply takes what the user entered, and prints it. However it is giving me the following error:

Fatal error: Cannot access empty property in /home/mbecerra/domains/phpeaurl.co.cc/public_html/create.php on line 15

create.php

<?php
// include Smarty Library
include('libs/Smarty.class.php');

// include Url Class
include('libs/UrlBinder.class.php');

// create object
$smarty = new Smarty;

// create an instance of the Url class
$turlbinder = new UrlBinder();

// set the url
$urlbinder->$url = $_POST['url'];

// assign user entered url
$smarty->assign('url', $urlbinder->url);

// assign pea url value
$smarty->assign('peaurl', "http://" . $_SERVER['HTTP_HOST'] . '/1');

//send headers
header("Cache-Control: must-revalidate");
header("Content-Type: text/html;charset=utf-8");

// display it
$smarty->display('create.tpl');
?>

UrlBinder.class.php

<?php
# Name: UrlBinder.class.php
# File Description: Class to manage urls and shorturls
# Author: PHPeaURL
# Web: http://www.phpeaurl.co.cc/
# Update: 2010-03-01
# Version: 1.0.0
# Copyright 2010 phpeaurl.co.cc


/*
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

class UrlBinder {

// url
private $url;

// short url id
private $shortcode;


// ********************************************************************
// Description: gets the value of requested member property 
// Parameters: member property which value is requested
// Returns: requested property members value
// ********************************************************************
public function __get($name) {
return $this->$name;
}


// ********************************************************************
// Description: sets the value of the requested member property
// Parameters: member property to set, value to set for member property
// ********************************************************************
public function __set($name, $value) {

// sanitize the value by removing whitespace, html tags and quoting strings with slashes
$this->$name = $value;
}
}
?>

Whats interesting is i have figured out that the line thats producing the error is:

// set the url
$urlbinder->$url = $_POST['url'];

However i don't see any problem with that line as its simply setting the property value. Any help in this matter would be greatly appreciated.

Sincerely,

PHPeaURL

It woun't let me edit the post above but, heres what my form looks like:
index.php

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>PHPeaURL - Shorten your URL</title>
<link rel="stylesheet" type="text/css" media="screen" href="templates/css/style.css" />
</head>
<body>
<h1>Welcome to PHPeaURL</h1>
<p>Are you sick of posting URLs in emails only to have it break when sent
causing the recipient to have to cut and paste it back together? Then you've
come to the right place. By entering in a URL in the text field below, we will
create a pea sized URL that will not break in email postings and never expires.</p>
<form action="create.php" method="post">
<fieldset>
<legend>Required</legend>
<label for="url">Url:<input type="text" id="url" tabindex="1" /></label>
<input type="submit" value="Shorten" tabindex="2" />
<input type="reset" value="Clear" tabindex="3" />
</fieldset>
</form>
</body>
</html>

Hope this helps,

Sincerely,

PHPeaURL

halojoy

Try

$urlbinder->url

For class variables (properties) this is the way to address them.

// set the url
$urlbinder->url = $_POST['url'];

//For example will display the current value
echo $urlbinder->url;

halojoy

Another thing.
private $url;
Private means only the class functions inside the class
can access this variable. And they are blocked from direct outside access.

To use $urlbinder->url variable like you do in your php script
by direct access from outside the class
you need to declare $url PUBLIC.
And possibly same for class variable $shortcode

class UrlBinder {

// url, we make it for open, public use
public $url;

// short url id
private $shortcode;