Question

I’m having a tough time sorthing this out. I’m working with a custom plugin system that presents things like this:

<plugin:class:method var1='hello', var2='yes' />

But, ‘:method’ and the variables do not have to exist – only the ‘class’ is required. For instace, this should still be ok:

<plugin:class />

The problem I’m having is how to I get the regex to conditionally return things when the method and/or variables do not exist. So far, I can get results when all the pieces exist, but not otherwise – this is where I’m at (struggling on the first conditional):

$f = "/<plugin:(?P<class>\w+)(?(?=^:)?P<method>\w+)\s+(.*)\/>/sUi";

Things are working very well with the following code, it’s simply a matter of being able to return all the pieces with the conditionals:

preg_replace_callback($f, array($this, 'processing'), $text);

Hope this makes some sense – and is even possible. Thanks.

Answer 1

The easiest and most maintainable way to do this would be to just get the whole plugin:class:method string with a simple /plugin:\S+/ expression, then explode(':', $string).

So, instead of the code above, you’d have something like:

$f = "/<plugin:(\S+)\s+(.*?)\/>/sUi";
if (preg_match($f, $string, $matches)) {
    $parts = explode($matches[1]);
    if (!in_array('method', $parts))
    {
        // do whatever needs done if "method" is not present
    }
    // ...
}