package Lingua::EN::FindNumber;

use 5.006;
our $VERSION = '1.2';

use strict;
use warnings;

use base 'Exporter';
our @EXPORT = qw( extract_numbers $number_re numify );

use Lingua::EN::Words2Nums;

# This is from Lingua::EN::Words2Nums, after being thrown through
# Regex::PreSuf
my $numbers =
	qr/((?:b(?:akers?dozen|illi(?:ard|on))|centillion|d(?:ecilli(?:ard|on)|ozen|u(?:o(?:decilli(?:ard|on)|vigintillion)|vigintillion))|e(?:ight(?:een|ieth|[yh])?|leven(?:ty(?:first|one))?|s)|f(?:i(?:ft(?:een|ieth|[yh])|rst|ve)|o(?:rt(?:ieth|y)|ur(?:t(?:ieth|[yh]))?))|g(?:oogol(?:plex)?|ross)|hundred|mi(?:l(?:ion|li(?:ard|on))|nus)|n(?:aught|egative|in(?:et(?:ieth|y)|t(?:een|[yh])|e)|o(?:nilli(?:ard|on)|ught|vem(?:dec|vigint)illion))|o(?:ct(?:illi(?:ard|on)|o(?:dec|vigint)illion)|ne)|qu(?:a(?:drilli(?:ard|on)|ttuor(?:decilli(?:ard|on)|vigintillion))|in(?:decilli(?:ard|on)|tilli(?:ard|on)|vigintillion))|s(?:core|e(?:cond|pt(?:en(?:dec|vigint)illion|illi(?:ard|on))|ven(?:t(?:ieth|y))?|x(?:decillion|tilli(?:ard|on)|vigintillion))|ix(?:t(?:ieth|y))?)|t(?:ee?n|h(?:ir(?:t(?:een|ieth|y)|d)|ousand|ree)|r(?:e(?:decilli(?:ard|on)|vigintillion)|i(?:gintillion|lli(?:ard|on)))|w(?:e(?:l(?:fth|ve)|nt(?:ieth|y))|o)|h)|un(?:decilli(?:ard|on)|vigintillion)|vigintillion|zero|s))/i;

my $ok_words  = qr/\b(and|a|of)\b/;
my $ok_things = qr/[^A-Za-z0-9.]/;
our $number_re = qr/\b(($numbers($ok_words|$ok_things)*)+)\b/i;

sub extract_numbers {
	my $text = shift;
	my @numbers;
	push @numbers, $1 while $text =~ /$number_re/g;
	s/\s+$// for @numbers;
	return @numbers;
}

sub numify {
	my $text = shift;
	$text =~ s/$number_re/words2nums($1). ($1 =~ m{(\s+)$} ? $1 :"")/eg;
	return $text;
}

1;
__END__

=head1 NAME

Lingua::EN::FindNumber - Locate (written) numbers in English text 

=head1 SYNOPSIS

  use Lingua::EN::FindNumber;
  my $text = "Fourscore and seven years ago, our four fathers...";

  numify($text); # "87 years ago, our 4 fathers..."

  @numbers = extract_numbers($text); # "Fourscore and seven", "four"

  while ($text =~ /$number_re/g) { # Build your own iterator
  

=head1 DESCRIPTION

This module provides a regular expression for finding numbers in English
text. It also provides functions for extracting and manipulating such
numbers.

=head1 EXPORTED METHODS

=head2 extract_numbers / numify / $number_re

  numify($text); # "87 years ago, our 4 fathers..."

  @numbers = extract_numbers($text); # "Fourscore and seven", "four"

  while ($text =~ /$number_re/g) { # Build your own iterator
  

=head1 SEE ALSO

This module was written for the Natural Languages chapter of the second
edition of Advanced Perl Programming. If you liked the module, why not
buy the book?

  http://www.amazon.co.uk/exec/obidos/ASIN/0596004567/tmtm-20

This module works rather well in conjunction with
L<Lingua::EN::Words2Nums>, which is a very cool module anyway. (And I
stole some of this module's code from it. Thanks, Joey!) It may also
be involved with L<Lingua::EN::NamedEntity> in the future, so check that
one out too.

=head1 AUTHOR

Current maintainer: Tony Bowden

Original author: Simon Cozens

=head1 BUGS and QUERIES

Please direct all correspondence regarding this module to:
  bug-Lingua-EN-Number@rt.cpan.org

=head1 COPYRIGHT AND LICENSE

Copyright 2003-2005 by Simon Cozens

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself. 

=cut