how to loop in templates?

[cold]

having developed this simple template engine for my own projects,the engine simply replaces the {replacable} tags with the appropriate value.
the template file is read into a string variable $string ,then i use preg_replace_callback to process the tags.
now,i have a problem with the loops.i've though about this:

{LOOP_NAME}
things to be {repeated}
{/LOOP}

then i though about using preg_replace_callback twice,once to extract the loop body,repeat it then insert it back into $string.
then use the final preg_replace_callback to replace all {replacable} variables.
is this a bad idea for server loads?

[bpat1434]

Is it not possible to use the SMARTY engine? It already has this functionality. And since your syntax is so close to it, I'd suggest you take a look at their code to see how they implement it.

[cold]

well..i've though about that.but the apps i'm building with this search engine are gonna be commercial.ad i've read that i will have to make my apps code available if i use somehting like smarty(GPL or LGPL)

and..learning from other's code,doesn't this violate the GPL license?
cause i've been into this debate for so long and no one could give me a clear answer.

regards

[bpat1434]

If it's licensed, and you decide to use portions of the code, yes you have to make it the same license. Now that is not to say that you can't look at how they do it, and develop your own code. The thing here is copying versus learning.

For example: Everything on this board is technically the thoughts and ideas of everyone who posts. If I give you code to use, you copy & paste it and don't give me credit, can I go after you? Probably not. But if I create program / script and you use the same methods to achieve a similar goal (looping in a template) but don't copy my code, can I go after you? Not really. Unless my source-code is closed (think Windows), it's legal to use the same ideas, as long as credit is given.

I'm not a lawyer, so i can't say it's not copyright infringement, but I can say that just because you look at it, doesn't mean you can't develop something very similar. Otherwise, how would we have the Zune, iPod, and Nomad? All serve the same function, all very similar, yet still somewhat different.

Anyway... back to your question. I guess me personally I would do something like this:

<?php
/*
 Assuming syntax of something like:
 {for start=0 max=10}
  <repeatable code />
 {/for}
*/
// The HTML output
$htmlOut = '';

preg_match('/{for start=([^\s]*) max=([^\s}]*)}(.*?){\/for}/i', $matches);
if(!empty($matches)) {
  // get rid of complete matched text
  array_shift($matches);

  for($i=0, $k=0, $max=count($matches); $i<$max; $k++) {
    $loop[$k]['start'] = $matches[$i++];
    $loop[$k]['end'] = $matches[$i++];
    $loop[$k]['text'] = $matches[$i++];
  }
  unset($matches);

  foreach($loop as $item)
  {
    for($i=$item['start']; $i<=$item['end']; $i++)
    {
      $htmlOut .= parseTplCode($item['text']);
    }
  }
}

// ... and so on and so on...
?>

That's just example code. Obviously it'd need tweaking and major refinement. But it's just an off the top of my head example.