Re: Regex question - identify which pattern comes first

[ikegami]

if ( /(BA[ABC]{2})|(CA[CD]{2})|(DA[SC]{2})/ ) {
   my $first =
     ( defined( $1 ) ? 1
     : defined( $2 ) ? 2
     :                 3
     );

   ...
}

local our $first;

/
   (?: BA[ABC]{2} (?{ $first = 1; })
   |   CA[CD]{2}  (?{ $first = 2; })
   |   DA[SC]{2}  (?{ $first = 3; })
/x;

Update: I had mixed up (??{ }) and (?{ }). Fixed.

[harangzsolt33]

Oh wow, that is an amazingly simple solution! Thank you so much!!! :-)

[LanX]

> that is an amazingly simple solution!

Did you try it?

These (??{ $first = 1; }) won't work because they'll include 1,2 or 3 into the regex.

Try (?{ $first = 1; }); with a single ? instead.

Thus

[harangzsolt33]

No, the second solution did not work. But the first one does work, and I never thought of doing it that way even though I knew you could capture using the parentheses. I didn't know you can use defined to figure out which one of the patterns was captured. The second solution, I think, requires a more modern Perl interpreter. I use Perl 5.8 mostly. It said unmatched regex --> / something... But it's okay. I'll use the first solution. I think, it's also easier to read.