sub match {
    my $context = (caller(1))[3];
    my $arg = shift;
    my @result = $arg =~ /$pattern/; #
    $context =~ /dirname/  ? $result[0] :
    $context =~ /basename/ ? $result[1] : ... # etc.
    # otherwise, return the whole result vector:
    @result
  }

  sub dirname  { &match }
  sub basename { &match }
  # etc.