I've got a template system where you can insert custom conditions like this:
HTML Code:
<if="$variable == 'value'">do this</if>
I can do that fine, but with nested conditions, the script screws up because the <if="">'s do not match with the correct </if>'s. Example:
Code:
<if="something"> <-- Will match with...
<if="something else">
yeah
</if> <-- this, instead of
</if> <-- this
I tried to solve this by re-calling the function in itself if there is another <if> statement nested within another one, this would evaluate the nested conditions so that no </if>'s remain, then the parent <if> will match up with the correct </if>. It's a little hard to wrap your head around, but if you understand then any help is appreciated
Here's my code,
PHP Code:
//============================================================================
// doConditions
// - execute conditions
//============================================================================
function doConditions($txt)
{
if(strpos($txt, '<if="') === false)
return $txt;
////////////////////////////////////////////////
// Set things up. More of a reference for me :)
////////////////////////////////////////////////
$if['s_start_len'] = strlen('<if="'); // IF start beginning length
$if['s_start_pos'] = false; // IF start beginning pos (<if=")
$if['s_end_len'] = strlen('">'); // IF start end length
$if['s_end_pos'] = false; // IF start end pos (">)
$if['cond_pos'] = false; // Position of starting condition
$if['s_last'] = false; // Last position of whole <if="">
$if['e_len'] = strlen('</if>'); // IF end length
$if['e_pos'] = false; // IF end pos (</if>)
$else['len'] = strlen('<else>'); // ELSE length
$else['pos'] = false; // ELSE pos (<else>)
$else['last'] = false; // Last position of whole <else>
$else['use'] = false; // Use else?
///////////////////////////////////
// Loop thru until nothing is left
///////////////////////////////////
while($if['s_start_pos'] = strpos($txt, '<if="') !== false)
{
////////////////////////////
// Fetch all this iffy info
////////////////////////////
$if['s_end_pos'] = strpos($txt, '">' , $if['s_start_pos']);
$if['s_last'] = $if['s_end_pos'] + $if['s_end_len'];
$if['e_pos'] = strpos($txt, '</if>', $if['s_last']);
$nested = strpos($txt, '<if="', $if['s_end_pos']);
if($nested !== false && $nested < $if['e_pos'])
{
$txt = substr($txt, 0, $if['s_last']) . $this->doConditions(substr($txt, $if['s_last']));
$if['e_pos'] = strpos($txt, '</if>', $if['s_last']);
}
$if['cond_pos'] = $if['s_start_pos'] + $if['s_start_len'] - 1;
//////////////////////
// See about the else
//////////////////////
$else['pos'] = strpos($txt, '<else>', $if['s_last']);
$else['last'] = $else['pos'] + $else['len'];
if($else['pos'] !== false && $else['pos'] < $if['e_pos'])
$else['use'] = true;
////////////////////////////
// Grab certain needed text
////////////////////////////
$__txt_all = '';
$__txt_cond = '';
$__txt_true = '';
$__txt_false = '';
$__txt_replace = '';
// All text for replacement later
$__txt_all = substr($txt, $if['s_start_pos'] - 1, $if['e_pos'] - $if['s_start_pos'] + $if['e_len'] + 1);
// Condition
$__txt_cond = substr($txt, $if['cond_pos'], $if['s_end_pos'] - $if['cond_pos']);
if(empty($__txt_cond))
$__txt_cond = 'true';
// True
if($else['use'])
$__txt_true = substr($txt, $if['s_last'], $else['pos'] - $if['s_last']);
else
$__txt_true = substr($txt, $if['s_last'], $if['e_pos'] - $if['s_last']);
// False
if($else['use'])
$__txt_false = substr($txt, $else['last'], $else['last'] - $if['e_pos']);
// Replacements
extract($this->vars, EXTR_OVERWRITE);
$__olde = error_reporting(E_ERROR);
eval('$__txt_replace = (' . $txt_cond . ' ? $txt_true : $txt_false);');
error_reporting($__olde);
/////////////////
// Lets dooo it!
/////////////////
$txt = str_replace($__txt_all, $__txt_replace, $__txt);
}
return $txt;
}
(btw, using preg_replace's would be no different
I was going to use regx techniques but there are a few advantages to using this way)
In all honesty, I didn't look too close at your code, but to answer your question, one proper way to implement this would be to use a stack (FILO). PHP offers the array_push and array_pop functions to accommodate this. You can figure out what data to store in the array (maybe an object containing the condition, result, and else result) but basically you'd just push for each new <IF> and pop for each </IF>
