NAME

Number::Range::Regex - create regular expressions that check for integers in a given range

SYNOPSIS

  use Number::Range::Regex;
  my $lt_20 = range( 0, 19 );

  print "foo($foo) contains an integer < 20" if $foo =~ /$lt_20/;
  print "foo($foo) is an integer < 20" if $foo =~ /^$lt_20$/;
  if( $line =~ /^\S+\s+($lt_20)\s/ ) {
    print "the second field ($1) is an integer < 20";
  }
  my $nice_numbers = rangespec( "42,175..192" );
  my $my_values = $lt_20->union( $nice_numbers );
  if( $line =~ /^\S+\s+($my_values)\s/ ) {
    print "the second field has one of my values ($1)";
  }

  my $lt_10        = rangespec( "0..9" );
  my $primes_lt_30 = rangespec( "2,3,5,7,11,13,17,19,23,29" );
  my $primes_lt_10 = $lt_10->intersection( $primes_lt_30 );
  my $nonprimes_lt_10 = $lt_10->minus( $primes_lt_30 );
  print "nonprimes under 10 contains: ".join",", $nonprimes_lt_10->to_string;
  if( $something =~ /^$nonprimes_lt_10$/ ) {
    print "something($something) is a nonprime less than 10";
  }
  if( $nonprimes_lt_10->contains( $something ) ) {
    print "something($something) is a nonprime less than 10";
  }
  
  my $octet = range(0, 255);
  my $ip4_match = qr/^$octet\.$octet\.$octet\.$octet$/;
  my $range_96_to_127 = range(96, 127);
  my $my_slash26_match = qr/^192\.168\.42\.$range_96_to_127$/;
  my $my_slash19_match = qr/^192\.168\.$range_96_to_127\.$octet$/;

  my $in_a_or_in_b_but_not_both = $a->xor($b);

  my $it = $range->iterator();
  $it->first;
  do { print $it->fetch } while ($it->next);
  $it->last;
  do { print $it->fetch } while ($it->prev);
  

DESCRIPTION

which is more legible - this?

  $date =~ m/^0*(?:[1-9]|[12][0-9]|3[01])\/0*(?:[0-9]|1[012])$/;

or this?

  my $day_range = range(1, 31);
  my $month_range = range(1, 12);
  $date =~ m/^$day_range\/$month_range$/;

(bonus points if you spotted the bug)

NOTES

It's usually better to check for number-ness only in the regular expression and verify the range of the number separately, eg: $line =~ /^\S+\s+(\d+)/ && $1 > 15 && $1 < 32; but it's not always practical to refactor in that way.

If you like one-liners, something like the following may suit you... m{^${\( range(1, 31) )}\/${\( range(1, 12) )}$} but, for readability's sake, please don't do that!

NOTES

Non-negative integers only for now.

BUGS AND LIMITATIONS

Please report any bugs or feature requests through the web interface at http://rt.cpan.org.

AUTHOR

Brian Szymanski <ski-cpan@allafrica.com> -- be sure to put Number::Range::Regex in the subject line if you want me to read your message.

SEE ALSO

perl(1), Number::Range, etc.