Template System Conditional

joe_C_nice

I was wondering if someone could point me to a source for information on adding conditional functionability to a template system.

I've come up with a system that uses html comment tags.

<!-- if: time_of_day > 12:00 -->
Good afternoon...
<!-- else -->
Good morning...
<!-- end_if: time_of_day > 12:00 -->

I'm using a regular expression to get this accomplished. However there is a problem, the problem being nested conditionals.

Problem:

<!-- if: time_of_day > 12:00 -->
<p>Good afternoon, 
  <!-- if: logged_in -->
  Mr. Smith
  <!-- else -->
  esteemed guest
  <!-- end_if: logged_in -->
<!-- else -->
Good morning...
<!-- end_if: time_of_day > 12:00 -->

One solution I've come up with is to add the conditional statement to the else comment tag.

Solution 1:

<!-- if: time_of_day > 12:00 -->
<p>Good afternoon, 
  <!-- if: logged_in -->
  Mr. Smith
  <!-- else: logged_in -->
  esteemed guest
  <!-- end_if: logged_in -->
<!-- else: time_of_day > 12:00 -->
Good morning...
<!-- end_if: time_of_day > 12:00 -->

Any further solutions to this problem would be greatly appreciated.

halojoy

Mybe you should
put such conditionals OUTSIDE of template.
This is the usual.
The very idea of Template is to separate PHP code from displaying.

simple template could be

<?php echo $header ?>

<body>
<?php echo $greeting ?>, <?php echo $username ?>.
<hr />

<div id="contents">
<?php include($contents_file); ?>
</div><-- end contents -->

<hr />
<?php echo $footer ?>

</body></html>

And the index.php

<?php

/* sample template 'main.tpl.htm' :
------------------------------------------------
<?php echo $header ?>

<body>
<?php echo $greeting ?>, <?php echo $username ?>.
<hr />

<div id="contents">
<?php include($contents_file); ?>
</div><-- end contents -->

<hr />
<?php echo $footer ?>

</body></html>
------------------------------------------------
*/

$username = 'Mr Smith';

$hour = date( 'H',  time() ); // hour= 00-23
$greeting = 'Good ';

if($hour < 5){
    $greeting .= 'Midnight';
}elseif($hour < 12){
    $greeting .= 'Morning';
}elseif($hour < 18){
    $greeting .= 'Afternoon';
}elseif($hour < 22){
    $greeting .= 'Evening';
}else{ // hour is 22-23
    $greeting .= 'Night';
}

$header   = '<html><head><title>page 1</title></head>';
$contents_file = './pages/index_stuff.htm';
$footer   = 'copyright $copy; me self';

// display it all
include('main.tpl.htm');

exit();

?>

halojoy

You can try my
google search for some good tutorials on
PHP Template use and good ways:
Google: php tutorial 2007 template basic OR simple

Like for example this tutorial:
http://designoahu.com/php-basic-template

regars 🙂
halojoy

joe_C_nice

Correct I'm trying to seperate the data logic from my presentation, but within my presentation I do require functionality in the form of conditional.

Here's the current reqular expression I'm using.

preg_match_all('/<!-- if: ([\w]+) (?:([<>=]) (\w+) )?-->((?:(?!<!-- else: \1 -->).)*)(?:<!-- else: \1 -->(.*))?<!-- end_if: \1 -->/s', $template, $conditional);

joe_C_nice

Here's a simple test for anyone wondering how this all works.

//Example 1.
//Both conditionals sections are top level, in that they aren't nested
$tpl = '<p>
<!-- if: time_of_day > 1200 -->
Good afternoon,
<!-- else: time_of_day -->
Good morning...
<!-- end_if: time_of_day -->

<!-- if: logged_in -->
  Mr. Smith
  <!-- else: logged_in -->
  esteemed guest
  <!-- end_if: logged_in -->
</p>';

//You'll notice two matches are returned
preg_match_all('/<!-- if: ([\w]+) (?:([<>=]) (\w+) )?-->((?:(?!<!-- else: \1 -->).)*)(?:<!-- else: \1 -->(.*))?<!-- end_if: \1 -->/s', $tpl, $arr);
print_r($arr);


//Example 2.
//One conditional section nested within the other
$tpl = '<p>
<!-- if: time_of_day > 1200 -->
Good afternoon,
 <!-- if: logged_in -->
  Mr. Smith
  <!-- else: logged_in -->
  esteemed guest
  <!-- end_if: logged_in -->
<!-- else: time_of_day -->
Good morning...
<!-- end_if: time_of_day -->
</p>';


//You'll notice only match is returned in this instance
preg_match_all('/<!-- if: ([\w]+) (?:([<>=]) (\w+) )?-->((?:(?!<!-- else: \1 -->).)*)(?:<!-- else: \1 -->(.*))?<!-- end_if: \1 -->/s', $tpl, $arr);
print_r($arr);

Ideally what I'd like is the match returned in example 2 to be similar to the matches returned in example 1. My current regular expression is negating matches if they are nested within another match.

joe_C_nice

Any further suggestions? I'm hoping someone with a better understanding of regular expressions might be able to offer some insight.

halojoy

I am not more than ordinary
with regular expressions.
There are others who have studied/used this more and are just great!

Are you sure you need all that advanced code, in your template?
Because, as I have shown in my previous post,
deal with it in some Custom Function with 'normal php code' is very easy and straightforward.

regars 🙂
halojoy