#!/usr/bin/perl
# filename: extract_dates.pl

use strict;
use warnings;
use Data::Dumper;
$Data::Dumper::Indent = 1;

my @dates;
push @dates, findMonth($_) while (<DATA>); 
print Dumper \@dates; # or do something else with your dates

sub findMonth {

    my @words = split / /,shift;

    my %months = map {$_ => 1 } qw/
        january jan february feb march     mar
        april   apr may      may june      jun
        july    jul august   aug september sep
        october oct november nov december  dec
    /;

    foreach (@words) {
        if (exists $months{lc($_)} ) {
            return extractDate(
                {
                    MONTH  => $_,
                    STRING => "@words"
                }
            );
            last;
        }
    }

    return;

}

sub extractDate {

    my $self = shift;

    return makeValidDate(
		{STRING=>$self->{STRING},DATE=>$1}
	) if ($self->{STRING} =~ 
		/
        (
            (?:
                (
                    [123]?\d
                    (st|nd|rd|th)?
                    \s+
                )?
                $self->{MONTH}
                \s\d{1,4}
                (
                    (-[123]?\d)?
                    (,\s[123]?\d\s)*
                    (and\s\d+)?
                    (,\s\d{4})?
                )?
            )
        )
        /x
    );
    
    return;

}

sub makeValidDate {

	my $self = shift;
	my ($string) = $self->{STRING} =~/^(.+)$/;

	$self->{DATE} =~s/-/X/g;
	$self->{DATE} =~s/(^-|\W|and|th|st|nd|rd)/ /gi;
	
	my @date = split /\s+/,$self->{DATE};
	my $date = {};

	foreach (@date) {

		if ($_=~/^\d{1,2}$/) {
			push @{$date->{days}},$_
		} elsif ($_=~/^\d{4}$/) {
			$date->{year} = $_
		} elsif ($_=~/(\d+)X(\d+)/) {
			push @{$date->{days}},$1 .. $2
		} else {
			$date->{month} = lc($_)
		}

	}

	use Date::Manip;
	my $out_date = {};
	
	foreach (@{$date->{days}}) {

		my $temp_date = ParseDate(
			$_ . " "
			. $date->{month} . " "
			. $date->{year}
		);

		$temp_date = &UnixDate($temp_date,"%D");
		push @{$out_date->{dates}},$temp_date;
		$out_date->{string} = $string;
	}

	return $out_date;

}

__DATA__
... the next social club meeting is on April 15, 1994...
... September 21-23, 1994 we will be hosting visitors...
... submissions should be made by 11 February 1994...
... Mail sent 7 Feb 1994...
... On the 16th September 1994 Mr X will be giving a talk on ...
... unconfirmed conference dates are March 4, 5 and 6, 1994...