PHP Notice: Undefined property: Tpl::$lbName - php

Question

I have a class Tpl to mount template with this function (template.php)
function Set($var, $value){
$this->$var = $value;
}
A php file that call the function, example (form.php):
$t->Set("lbAddress","Address");
And a html file with the template with tags (template.html)
<tr><td>[lbAdress]</td></tr>
To print the html I have this function (template.php) - the notice points to this function
function Show_Temp($ident = ""){
// create array
$arr = file($this->file);
if( $ident == "" ){
$c = 0;
$len = count($arr);
while( $c < $len ){
$temp = str_replace("[", "$" . "this->", $arr[$c]);
$temp = str_replace("]", "", $temp);
$temp = addslashes($temp);
eval("\$x = \"$temp\";");
echo $x;
$c++;
}
} else {
$c = 0;
$len = count($arr);
$tag = "*=> " . $ident;
while( $c < $len ){
if( trim($arr[$c]) == $tag ){
$c++;
while( (substr(#$arr[$c], 0 ,3) != "*=>" ) && ($c < $len) ){
$temp = str_replace("[", "$" . "this->", $arr[$c]);
$temp = str_replace("]", "", $temp);
$temp = addslashes($temp);
eval("\$x= \"$temp\";"); //this is the line 200
echo $x;
$c++;
}
$c = $len;
}
$c++;
}
}
}
If the template .html have a line [lbName] and I don't have the line $t->Set("lbName","Name"); at the php code, I receive the error PHP Notice: Undefined property: Tpl::$lbName in ../template.php(200) : eval()'d code on line 1. The solution that I found is add lines like $t->Set("lbName","");, but if I have 50 tags in HTML that I don't use in PHP, I have to add all 50 $t->Set("tag_name","");. The error occurred after migrate to the PHP 5.
Can someone help me? Thanks

Answer 1

Perhaps a better way still would be not to rely on dynamic evaluation through eval (it's generally best to avoid eval where possible), but to replace [lbName] with the value stored in the object directly as and when needed. If you can replace [lbName] with $this->lbName, surely you can also replace it with the value of lBName that you've looked up on-the-fly?
To answer your original question, however:
If I understand correctly, you're setting the values like this:
$t->Set('foo', 'bar');
And – effectively – getting them like this:
$t->foo;
If so, you could implement a __get method to intercept the property references and provide your own logic for retrieving the value; e.g.:
public function __get($key)
{
// You can adapt this logic to suit your needs.
if (isset($this->$key))
{
return $this->$key;
}
else
{
return null;
}
}
In this case, you'd probably be better off using an associative array as the backing store, and then using __get and __set to access it; e.g.:
class Template
{
private $values = array();
public function __get($key)
{
if (array_key_exists[$key, $this->values])
{
return $this->values[$key];
}
else
{
return null;
}
}
public function __set($key, $value)
{
$this->values[$key] = $value;
}
}