help with regex match

marcnyc

wrote this RegEx line:

    $dp = preg_replace('/(.*'.$definition.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);

which is supposed to extrapolate a value of the property of a CSS definition. In other words if my CSS is:

#mydiv {
    width: 100px;
}

$dp is supposed to return '100px' with $definition = '#mydiv' and $property = 'width';

The code seems to work (but let me know if you see something wrong) except for the fact that it also matches 'mydiv' or '.mydiv'. Could you please help me change the code so that if I have $definition = '#mydiv' in ONLY matches #mydiv and not 'mydiv' or '.mydiv'?

I was thinking that since all the $definitions are at the beginning of a new line I could try to change it so it matches ALL of $definition from the beginning of a line but I don't know how to do this and I don't know if it's the best way. I'm open to suggestions.

The code is supposed to work for all different kind of CSS definitions and properties.

Thanks for your help!

Derokorian

Are you sure definition is defined as #mydiv? Because when I run the below code, I only receive 100px back, as expected.

<?php

$definition = '#mydiv';
$property = 'width';
$css = <<<CSS

#mydiv {
    width: 100px;
}

.mydiv {
    width: 200px;
}

mydiv {
    width: 300px;
}
CSS;
$dp = preg_replace('/(.*'.$definition.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css); 

echo $dp;

marcnyc

That's EXACTLY the problem I have... that regex matches #mydiv, .mydiv and mydiv and I want it to ONLY match whatever value I pass via $definition. When I pass #mydiv it's looking for 'mydiv' instead and I want it to look for #mydiv
Thanks for your reply and time!

marcnyc

Upon further examination I have noticed that it does match #mydiv correctly but it thinks that .mydiv and mydiv are the same, as if the dot makes no difference...

I've tried adding this

	if ( substr( $definition, 0, 1 ) === "." )
		$definition_property = preg_replace('/(.*\.'.$definition.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);
	else
		$definition_property = preg_replace('/(.*'.$definition.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);

in my function but it doesn't help...
somehow the dot is not being considered a part of the .mydiv string

Weedpacket

I think you would be better off writing (or finding) a proper CSS parser. Especially as you need this to work with "all different kind of CSS definitions and properties".

bradgrafelman

Definitely agree with Weedpacket above - just because you have a hammer doesn't mean you can treat everything like a nail. Regexp might not be the best candidate for the job.

However, if you're stuck with trying to make this work, you might want to look into using [man]preg_quote/man on the values being searched on (since, for example, a period more or less means "match any character" in regular expression syntax).

marcnyc

not sure what a CSS parser is...
thanks for the the preg_quote suggestion, I thought it worked but even with that I still had the issue of 'mydiv' matching both '.mydiv' and '#mydiv'

This morning I came up with this solution which appears to work... I am sure it is not the most correct but it appears to work so I was wondering if you could review it and let me know what you think:

function tbs_css_find($definition,$property) {
	global $css;
	$definition_encoded = PostFriendlyCSS_encode($definition);
	echo $definition;
	if ( substr($definition, 0, 1) == '.' ) {
		$css = str_replace($definition,$definition_encoded,$css);
		$definition_property_value = preg_replace('/(.*'.$definition_encoded.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);
	} else if ( substr($definition, 0, 1) == '#' ) {
		$css = str_replace($definition,$definition_encoded,$css);
		$definition_property_value = preg_replace('/(.*'.$definition_encoded.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);
	} else if ( preg_match('/^\b'.$definition_encoded.'\b/im',$css) ) {
		$definition_property_value = preg_replace('/(.*^\b'.$definition_encoded.'\b.*?\s'.$property.':)([^;]*)(.*)/ism','$2',$css);
	} else {
		$definition_property_value = preg_replace('/(.*'.$definition.'.*?\s'.$property.':)([^;]*)(.*)/is','$2',$css);
	}
	return trim($definition_property_value);
}

function PostFriendlyCSS_encode($definition) {
	$definition = str_replace('#','%%%pound%%%',$definition);
	$definition = str_replace('.','%%%dot%%%',$definition);
	$definition = str_replace(',','%%%comma%%%',$definition);
	$definition = str_replace(':','%%%semicolon%%%',$definition);
	$definition = str_replace('=','%%%equal%%%',$definition);
	$definition = str_replace('"','%%%quote%%%',$definition);
	$definition = str_replace('[','%%%lbracket%%%',$definition);
	$definition = str_replace(']','%%%rbracket%%%',$definition);
	$definition = str_replace(' ','%%%space%%%',$definition);
	return $definition; 
}

To make sure I was only matching 'mydiv' and not '.mydiv' and '#mydiv' I added the \b word-boundry to the preg_replace and the multi-line 'm' modifier AND I am matching for a definition at the beginning of a new line.

I am going with the assumption that every new CSS definition is at the beginning of a new line, as it is in every or most CSS files I've ever seen... so I guess this will break if there is a CSS definition that is not at the beginning of a line but at this point I can't think of a better solution...

of course I am open to suggestions...