Regex question

ultranerds has asked for the wisdom of the Perl Monks concerning the following question:

Hi guys,

First of all, lemme show you some example values I need to match:

[url]http://www.test.com[/url]
[img]http://www.site.com/image.jpg[/img]
[url http://www.test.com]name of link[/url]
[citation]some quote here[/quote]
[download]

Now, I have this regex:

    while ($_[0] =~ /\[(\/?)(lien|url|citation|img).+?\]/sg) { 
        print "GOT: $1 and $2 \n";
    }
[download]

..which is meant to capture the / (if it exists, after the [, and assign to $1), and then also capture to tag name itself to $2)

However, it doesn't seem to work (it only picks up the ones without the / in the tag)

If I change the regex to remove .+? , so we have:

    while ($_[0] =~ /\[\/?(lien|url|citation|img)\]/sg) { 
        print "BLA: $1 \n";
    }
[download]

..it works, but obviously doesn't pick up stuff like:

[url http://www.test.com]some text[/url]

Anyone got any suggestions?

UPDATE: I think I've worked it out - I needed .*? instead of .+? , cos .*? can mean 0 or more results, whereas .+? means "at least 1")

TIA

Andy

Comment on Regex question Select or Download Code

Replies are listed 'Best First'.
Re: Regex question by moritz (Cardinal) on Sep 22, 2011 at 15:18 UTC
Maybe Parse::BBCode would be worth looking at. Perl 6 - second systems done right	[reply]
Re: Regex question by Anonymous Monk on Sep 22, 2011 at 15:12 UTC
Anyone got any suggestions? :) Use a module already? ;) This is what you have use YAPE::Regex::Explain; print YAPE::Regex::Explain ->new( qr/\[(\/?)(lien\|url\|citation\|img).+?\]/s )->explain; __END__ The regular expression: (?s-imx:\[(/?)(lien\|url\|citation\|img).+?\]) matches as follows: NODE EXPLANATION ---------------------------------------------------------------------- (?s-imx: group, but do not capture (with . matching \n) (case-sensitive) (with ^ and $ matching normally) (matching whitespace and # normally): ---------------------------------------------------------------------- \[ '[' ---------------------------------------------------------------------- ( group and capture to \1: ---------------------------------------------------------------------- /? '/' (optional (matching the most amount possible)) ---------------------------------------------------------------------- ) end of \1 ---------------------------------------------------------------------- ( group and capture to \2: ---------------------------------------------------------------------- lien 'lien' ---------------------------------------------------------------------- \| OR ---------------------------------------------------------------------- url 'url' ---------------------------------------------------------------------- \| OR ---------------------------------------------------------------------- citation 'citation' ---------------------------------------------------------------------- \| OR ---------------------------------------------------------------------- img 'img' ---------------------------------------------------------------------- ) end of \2 ---------------------------------------------------------------------- .+? any character (1 or more times (matching the least amount possible)) ---------------------------------------------------------------------- \] ']' ---------------------------------------------------------------------- ) end of grouping ---------------------------------------------------------------------- [download] What do you think is wrong with your regex?	[reply] [d/l]
Re^2: Regex question by ultranerds (Hermit) on Sep 22, 2011 at 15:21 UTC
Yeah, this part ;) `.+? any character (1 or more times (matching the least amount possible))` [download] As I updated in the above thread - I changed it to .*? and it works perfectly :)	[reply] [d/l]