Break my regex, please

[patgas]

I'm extracting some information from a line in a data file, and I came up with following regex to do it. I have two questions: What would break it, and why doesn't $title have the space in between END OF CENTURY and <BASIC> ? I'd have thought that using the negated character class to grab END OF CENTURY would take everything up until the next <, but it knows to leave out the space immediately before.

$_ = "(KONAMI ORIGINAL) END OF THE CENTURY <BASIC> / NO.9";
m|^\(([^\)]*)\) ([^<]*) <([^>]*)> / (.*)$|;
( $source, $title, $mode, $artist ) = ( $1, $2, $3, $4 );
print ">$source< >$title< >$mode< >$artist<\n";

[davorg]

The space is used to match the space in you regex between the second and third set of parentheses.

--
<http://www.dave.org.uk>

"The first rule of Perl club is you don't talk about Perl club."

[tommyw]

The second questions easier to answer: the spaces in your pattern match the spaces in the text. So if you want the $title to include the surrounding spaces, use: m|^\(([^\)]*)\)([^<]*)<([^>]*)> / (.*)$|;

As to what could break it, that depends on what you're trying to do :-). Anything not in that format wouldn't behave the way you expect. Particularly if the title happens to include a < character.

--
Tommy
Too stupid to live.
Too stubborn to die.

[jeffa]

Lots could break this - you'll just have to test it more.

As for that space, the reason why you are not grabbing it in $3 is because you are specifying a space before the slash. Try this: (altered to be strict compliant)

$_ = "(KONAMI ORIGINAL) END OF THE CENTURY <BASIC> / NO.9";
my ($source,$title,$mode,$artist) = m|^\(([^\)]*)\) ([^<]*)<([^>]*)> /
+ (.*)$|;
print ">$source< >$title< >$mode< >$artist<\n";

Also, i recommend using \s with a * or a + instead of literal spaces in your regex.

jeffa

[doc]

You are using literal spaces to match literal spaces. Adding/removing a single extra space will destroy the match, as will the presence of extra parentheses These are a few of the things that break your regex:

(KONAMI ORIGINAL) END OF THE CENTURY <BASIC>  / NO.9
(KONAMI ORIGINAL) END OF THE CENTURY <BASIC>/ NO.9
(KONAMI ORIGINAL) END OF THE CENTURY<BASIC> / NO.9
(KONAMI ORIGINAL)END OF THE CENTURY <BASIC> / NO.9
(KONAMI ORIGINAL (no 9) ) END OF THE CENTURY <BASIC> / NO.9

using \s+ where one or more spaces is likely and \s* where 0 or more are OK is better if humans are involved in the typing!

doc