PCRE Help

[My220x]

I am new to PCRE in PHP and understand the basic patterns however the ones below are a bit complex and I don't understand what the following pattern matches:

$ret = preg_replace("#(^|[\n ])([\w]+?://[\w\#$%&~/.\-;:=,?@\[\]+]*)#... "<a href='' rel='nofollow'></a>", $ret);

$ret = preg_replace("#(^|[\n ])((www|ftp)\.[\w\#$%&~/.\-;:=,?@\[\]+]*... "<a href='http://' rel='nofollow'></a>", $ret); 

Could someone please explain and link me to some good tuts. Thanks.

[My220x]

No replies, is anyone good at PCRE here?

It doesn't matter anyway now I worked out the first one matches a url with :// in it and the second one matches a url with www. or ftp.