
=head1 NAME

POD2::Base - Base module for translations of Perl documentation

=head1 SYNOPSIS

    use POD2::Base;
    $pod2 = POD2::Base->new({ lang => 'EO' });

    @dirs = $pod2->pod_dirs;
    $re = $pod2->search_perlfunc_re;

=head1 DESCRIPTION

This module is an abstraction of the code in POD2::IT 
and POD2::FR. These modules belong to the Italian and 
the French translation projects of core Perl pods.

Once a translation package had been installed, the translated 
documentation can be accessed with: 

    $ perldoc POD2::<lang>::<podname>

(where <lang> is a language abbreviation like IT, FR,
TLH, etc.)

This is guaranteed to work even for older versions of
L<perldoc|perldoc>. It is not very convenient but always works.

To improve the support to read translated docs, the
L<perldoc|perldoc> utility (since version 3.14_01) was updated 
to find translated PODs via:

    $ perldoc -L IT <podpage>
    $ perldoc -L FR -f <function>
    $ perldoc -L TH -q <FAQregex>

(I<Note>: this support was shipped together with the
recently released 5.10.0 version the Perl interpreter.)

The objective of this class is to provide a minimum
base to help C<perldoc> and authors of translation
packages to do their job.

=head1 SUBCLASSING

If you want to write a translation package (and have
some customization needs), your
work may be diminished if you subclass C<Pod::Base>.

For example, a minimum example is provided below:

    package POD2::TLH; # Klingon

    use POD2::Base;
    our @ISA = qw( POD2::Base );

    sub search_perlfunc_re { # makes 'perldoc -f' work
        return 'Klingon Listing of Perl Functions';
    }

    1;

And then

    $ perldoc -L tlh perlintro

will present you the introduction of Perl in Klingon language 
(provided a F<POD2/TLH/perlintro.pod> file was shipped together
with F<POD2/TLH.pm>) and

    $ perldoc -L tlh -f pack

will find you the Klingon documentation of C<pack> (if
F<POD2/TLH/perlfunc.pod> was made available as well).

=head1 METHODS

This module has been made into a proper class
with a very small API.

=over 4

=item B<new>

    $pod2 = POD2::Base->new(\%args);
    $pod2 = POD2::ANY->new();

The constructor. An actual call might look like this:

    $pod2 = POD2::Base->new({ lang => 'tlh' });

where the supported options are:

=over 4 

=item * "lang"

Specifies the language code we're interested in.
This is required, but can be extracted from
the name of a subclass. Read below.

=item * "inc"

This is used to override the list of Perl
library directories where POD documents 
are searched (namely, C<@INC>). Most of the
time, you don't want to mess with that.
It's handy for debugging and testing.

It must be an array ref.

=back

If C<POD2::ANY> is a subclass of C<POD2::Base>, the
inherited constructor will work without arguments
pulling 'ANY' from the package name and using it
as the intented language code.

Note that use of "inc" in the constructor
freezes the list of library dirs searched by the
C<POD2::Base> instance. If this is not used,
the up-to-date C<@INC> is used at each call
of C<pod_dirs> (so that dynamic changes in
the Perl library path are taken into account).
That's what we meant with the
"Most of the time, you don't want to mess with that" 
mentioned above.

=item B<pod_dirs>

    @dirs = $pod2->pod_dirs;
    @dirs = $pod2->pod_dirs(\%options);

Used by C<Pod::Perldoc> to find out where to
look for translated pods. 

The C<POD2::Base> default behavior is to find
F<< POD2/<lang>/ >> directories under the
current Perl library directories (C<@INC>) or
the list given as argument "inc" in the constructor.

The supported options are:

=over 4

=item * "test"

By default, the return of C<pod_dirs> do not
include POD directories which do not exist (tested
with C<-d>). If an explicit false value for this option (like
C<< test => 0 >>) is given, such test is not done
and C<pod_dirs> includes all possible candidates
F<< POD2/<lang>/ >> under the library directories.
(Handy for debugging this module. Not much practical
use for anything else.)

=back

=item B<search_perlfunc_re>

    $re = $pod2->search_perlfunc_re; 

To implement C<< perldoc -f <function> >>
the current code of C<Pod::Perldoc> uses a hard coded string
"Alphabetical Listing of Perl Functions" or the return
of this method (in a regexp) to skip the introduction
and reach the listing of core functions.
Thus a translation package with a corresponding translated
F<perlfunc.pod> should define this method to 
make C<< perldoc -L <lang> -f <function> >>
work properly.

=back

There are other methods documented below. However,
they will probably be superseded in future versions
when more general methods to find and display metadata
on translated PODs are designed and implemented.

=over 4

=item B<pod_info>

    $hashref = $pod2->pod_info;

Used by C<POD2::Base> itself. The return contains
some metadata on the translated PODs which is used
by the methods C<print_pod> and C<print_pods>.

When subclassing, you B<should> override this
with the current information on what POD
translations the current package is providing.

=item B<print_pods>

    $pod2->print_pods;

Prints all translated pods and the corresponding Perl version
of the original files.

=item B<print_pod>

    $pod2->print_pod(@pages);
    $pod2->print_pod(); # uses @ARGV

Prints the corresponding Perl version of the original files
corresponding to the pods passed as arguments.

=back

=head1 EXAMPLES

=head2 POD2::TLH

A slightly extended version of C<POD2::TLH> 
goes like this:

    package POD2::TLH; # Klingon

    use POD2::Base;
    our @ISA = qw( POD2::Base );

    sub search_perlfunc_re {
        return 'Klingon Listing of Perl Functions';
    }

    sub pod_info {
        return { perlintro => '5.8.8' };
    }

    1;

And you may try:

    use POD2::TLH;
    my $pod2 = 'POD2::TLH';
    $pod2->print_pods();
    $pod2->print_pod('pod_foo', 'pod_baz', ...); 

=head2 THE INSTALLED FILES

If you want to find out which language-specific
POD files are installed at your Perl,
you could use a code similar to this.

    use File::Find;
    use POD2::Base;

    my $pod2 = POD2::Base->new({ lang => $lang });

    my @files;
    find sub { push @files, $File::Find::name } if -f },
         $pod2->pod_dirs;
    print "$_\n" for @files;

In the C<POD2-Base> distribution tarball, a script
F<eg/list.pl> is included with an improved
version of this code.

The rules of finding POD in F<.pod>, F<.pm> files and others
belong to L<Pod::Perldoc>. So C<POD2::Base> do not try
to repeat them here.


=head1 AUTHORS

Enrico Sorcinelli E<lt>bepi at perl.itE<gt> (the original POD2::IT code)

Adriano Ferreira E<lt>ferreira at cpan.orgE<gt>

=head1 SEE ALSO

L<POD2::IT>, L<POD2::FR>, L<POD2::LT>, L<POD2::CN>, L<perldoc>, L<perl>.

=head1 COPYRIGHT AND LICENCE

Copyright (C) 2004-2006 Perl.it / Perl Mongers Italia

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

=cut
