use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new(qr/[\S*\W*]/)->explain;
__END__
The regular expression:

(?-imsx:[\S*\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):
----------------------------------------------------------------------
  [\S*\W*]                 any character of: non-whitespace (all but
                           \n, \r, \t, \f, and " "), '*', non-word
                           characters (all but a-z, A-Z, 0-9, _), '*'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------