use YAPE::Regex::Explain;
my $re = '[\w\d]+(^:[\w\d]+:$)\w+';
print YAPE::Regex::Explain->new($re)->explain();
__END__
The regular expression:
(?-imsx:[\w\d]+(^:[\w\d]+:$)\w+)
matches as follows:
NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
[\w\d]+ any character of: word characters (a-z, A-
Z, 0-9, _), digits (0-9) (1 or more times
(matching the most amount possible))
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
^ the beginning of the string
----------------------------------------------------------------------
: ':'
----------------------------------------------------------------------
[\w\d]+ any character of: word characters (a-z,
A-Z, 0-9, _), digits (0-9) (1 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
: ':'
----------------------------------------------------------------------
$ before an optional \n, and the end of
the string
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
\w+ word characters (a-z, A-Z, 0-9, _) (1 or
more times (matching the most amount
possible))
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
Also note that, since \d is a subset of \w,
[\w\d] is the same as (and more simply coded as) [\w]. |