currency.pod

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=head1 NAME

Locale::Currency - ISO three letter codes for currency identification (ISO 4217)

=head1 SYNOPSIS

    use Locale::Currency;

    $curr = code2currency('usd');     # $curr gets 'US Dollar'
    $code = currency2code('Euro');    # $code gets 'eur'

    @codes   = all_currency_codes();
    @names   = all_currency_names();


=head1 DESCRIPTION

The C<Locale::Currency> module provides access to the ISO three-letter
codes for identifying currencies and funds, as defined in ISO 4217.
You can either access the codes via the L<conversion routines>
(described below),
or with the two functions which return lists of all currency codes or
all currency names.

There are two special codes defined by the standard which aren't
understood by this module:

=over 4

=item XTS

Specifically reserved for testing purposes.

=item XXX

For transactions where no currency is involved.

=back


=head1 CONVERSION ROUTINES

There are two conversion routines: C<code2currency()> and C<currency2code()>.

=over 4

=item code2currency()

This function takes a three letter currency code and returns a string
which contains the name of the currency identified. If the code is
not a valid currency code, as defined by ISO 4217, then C<undef>
will be returned.

    $curr = code2currency($code);

=item currency2code()

This function takes a currency name and returns the corresponding
three letter currency code, if such exists.
If the argument could not be identified as a currency name,
then C<undef> will be returned.

    $code = currency2code('French Franc');

The case of the currency name is not important.
See the section L<KNOWN BUGS AND LIMITATIONS> below.

=back


=head1 QUERY ROUTINES

There are two function which can be used to obtain a list of all
currency codes, or all currency names:

=over 4

=item C<all_currency_codes()>

Returns a list of all three-letter currency codes.
The codes are guaranteed to be all lower-case,
and not in any particular order.

=item C<all_currency_names()>

Returns a list of all currency names for which there is a corresponding
three-letter currency code. The names are capitalised, and not returned
in any particular order.

=back


=head1 EXAMPLES

The following example illustrates use of the C<code2currency()> function.
The user is prompted for a currency code, and then told the corresponding
currency name:

    $| = 1;    # turn off buffering

    print "Enter currency code: ";
    chop($code = <STDIN>);
    $curr = code2currency($code);
    if (defined $curr)
    {
        print "$code = $curr\n";
    }
    else
    {
        print "'$code' is not a valid currency code!\n";
    }

=head1 KNOWN BUGS AND LIMITATIONS

=over 4

=item *

In the current implementation, all data is read in when the
module is loaded, and then held in memory.
A lazy implementation would be more memory friendly.

=item *

This module also includes the special codes which are
not for a currency, such as Gold, Platinum, etc.
This might cause a problem if you're using this module
to display a list of currencies.
Let Neil know if this does cause a problem, and we can
do something about it.

=item *

ISO 4217 also defines a numeric code for each currency.
Currency codes are not currently supported by this module,
in the same way Locale::Country supports multiple codesets.

=item *

There are three cases where there is more than one
code for the same currency name.
Kwacha has two codes: mwk for Malawi, and zmk for Zambia.
The Russian Ruble has two codes: rub and rur.
The Belarussian Ruble has two codes: byr and byb.
The currency2code() function only returns one code, so
you might not get back the code you expected.

=back

=head1 SEE ALSO

=over 4

=item Locale::Country

ISO codes for identification of country (ISO 3166).

=item Locale::Script

ISO codes for identification of written scripts (ISO 15924).

=item ISO 4217:1995

Code for the representation of currencies and funds.

=item http://www.bsi-global.com/iso4217currency

Official web page for the ISO 4217 maintenance agency.
This has the latest list of codes, in MS Word format. Boo.

=back

=head1 AUTHOR

Michael Hennecke E<lt>[e-mail]<gt>
and
Neil Bowers E<lt>[e-mail]<gt>

=head1 COPYRIGHT

Copyright (C) 2002-2004, Neil Bowers.

Copyright (c) 2001 Michael Hennecke and
Canon Research Centre Europe (CRE).

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

=cut