README

Abstract

Regular expressions can be hard in PHP, especially if you want proper error handling. The OBF RegExp component helps with that. It also offers an easier access to the regexp match groups in the form of an object.

Installation

To install the OBF RegExp component, use composer:

composer require obf/regexp

Usage

Warning

The OBF implementation differs from the PHP implementation in some minor details:

• By default, the DOLLAR_ENDONLY (D) modifier is set for all regular expressions. This can be changed by setting the $pcreDollarEndOnlyBehavior parameter to true. (We think the original behavior is braindead.)

Performing a regular expression match

To do a RegExp match, use the RegExp::match() function:

if (RegExp::match('/^[a-z]+$', 'asdf')) {
    // Do something 
}

Getting match groups for a match

The third parameter of the RegExp::match() function is a variable passed by reference. After a successful match, this variable will contain a RegExpMatch object, which can be used to get a specific match group:

if (RegExp::match('/([A-Z])([0-9])/', 'A1', $match)) {
    echo($match[0]);
    echo($match->getMatchGroup(0));
}

Counting matches

If you want to perform multiple matches, you can do so with the RegExp::matchAll() function:

$count = RegExp::matchAll('/[A-Z][0-9]/', 'A1B2C3');

The $count variable will contain the number of matches.

Getting match groups for multiple matches

The RegExp::matchAll() function also accepts a parameter for matches, but instead of a single RegExpMatch object, it will contain an array of a RegExpMatch:

RegExp::matchAll('/(?P<letter>[A-Z])([0-9])/', 'A1B2C3', $matches);
foreach ($matches as $match) {
	echo($match->getMatchGroup('letter'));
}

Handling errors

Sometimes you are using regular expressions from untested or unreliable sources. Fortunately, RegExp provides a proper exception for these cases:

try {
    if (RegExp::match('/[a-z]', 'asdf')) {
        // Do something
    }
} catch (RegExpError $e) {
    // Handle error
}

License

This library is published under the MIT license.