NAME

Perl::Tags - Generate (possibly exuberant) Ctags style tags for Perl sourcecode

SYNOPSIS

        use Perl::Tags;
        my $naive_tagger = Perl::Tags::Naive->new( max_level=>2 );
        $naive_tagger->process(
            files => ['Foo.pm', 'bar.pl'],
            refresh=>1 
        );

Recursively follows use and require statements, up to a maximum of max_level.

The implemented tagger, Perl::Tags::Naive is a more-or-less straight ripoff, slightly updated, of the original pltags code, and is rather naive. It should be possible to subclass using something like PPI or Text::Balanced, though be aware that this is alpha software and the internals are subject to change (so get in touch to let me know what you want to do and I'll try to help).

FEATURES

    * Recursive, incremental tagging.
    * parses `use_ok`/`require_ok` line from Test::More

USING with VIM

Perl::Tags is designed to be used with vim. My ~/.vim/ftplugin/perl.vim contains the following:

    setlocal iskeyword+=:  " make tags with :: in them useful

    if ! exists("s:defined_functions")
    function s:init_tags()
        perl <<EOF
            use Perl::Tags;
            $naive_tagger = Perl::Tags::Naive->new( max_level=>2 );
                # only go one level down by default
    EOF
    endfunction

    " let vim do the tempfile cleanup and protection
    let s:tagsfile = tempname()

    function s:do_tags(filename)
        perl <<EOF
            my $filename = VIM::Eval('a:filename');

            $naive_tagger->process(files => $filename, refresh=>1 );

            my $tagsfile=VIM::Eval('s:tagsfile');
            VIM::SetOption("tags+=$tagsfile");

            # of course, it may not even output, for example, if there's nothing new to process
            $naive_tagger->output( outfile => $tagsfile );
    EOF
    endfunction

    call s:init_tags() " only the first time

    let s:defined_functions = 1
    endif

    call s:do_tags(expand('%'))

    augroup perltags
    au!
    autocmd BufRead,BufWritePost *.pm,*.pl call s:do_tags(expand('%'))
    augroup END

Note the following:

You will need to have a vim with perl compiled in it. Debuntu packages this as vim-perl. Alternatively you can compile from source (you'll need Perl + the development headers libperl-dev).
The EOF in the examples has to be at the beginning of the line (the verbatim text above has leading whitespace)

METHODS

`new`

Perl::Tags is an abstract baseclass. Perl::Tags::Naive is provided and can be instantiated with new.

    $naive_tagger = Perl::Tags::Naive->new( max_level=>2 );

Accepts the following parameters

    max_level:    levels of "use" statements to descend into, default 2
    do_variables: tag variables?  default 1 (true)
    exts:         use the Exuberant extensions

`to_string`

A Perl::Tags object will stringify to a textual representation of a ctags file.

    print $tagger;

`clean_file`

Delete all tags, but without touching the "order" seen, that way, if the tags are recreated, they will remain near the top of the "interestingness" tree

`output`

Save the file to disk if it has changed. (The private {is_dirty} attribute is used, as the tags object may be made up incrementally and recursively within your IDE.

`process`

Scan one or more Perl file for tags

    $tagger->process( 
        files => [ 'Module.pm',  'script.pl' ] 
    );
    $tagger->process(
        files   => 'script.pl',
        refresh => 1,
    );

`queue`, `popqueue`

Internal methods managing the processing

`process_item`, `process_file`

Do the heavy lifting for process above.

`register`

The parsing is done by a number of lightweight objects (parsers) which look for subroutine references, variables, module inclusion etc. When they are successful, they call the register method in the main tags object.

`get_parsers`

Return the parses for this object. Abstract, see Perl::Tags::Naive below.

`Perl::Tags::Naive`

A naive implementation. That is to say, it's based on the classic pltags.pl script distributed with Perl, which is by and large a better bet than the results produced by ctags. But a "better" approach may be to integrate this with PPI.

Subclassing

See TodoTagger in the t/ directory of the distribution for a fully working example (tested in <t/02_subclass.t>). You may want to reuse parsers in the ::Naive package, or use all of the existing parsers and add your own.

    package My::Tagger;
    use Perl::Tags;
    our @ISA = qw( Perl::Tags::Naive );

    sub get_parsers {
        my $self = shift;
        return (
            $self->can('todo_line'),     # a new parser
            $self->SUPER::get_parsers(), # all ::Naive's parsers
            # or maybe...
            $self->can('variable'),      # one of ::Naive's parsers
        );
    }

    sub todo_line { 
        # your new parser code here!
    }
    sub package_line {
        # override one of ::Naive's parsers
    }

Because ::Naive uses can('parser') instead of \&parser, you can just override a particular parser by redefining in the subclass.

`get_parsers`

The following parsers are defined by this module.

trim

A filter rather than a parser, removes whitespace and comments.

variable

Tags definitions of my, our, and local variables.

Returns a Perl::Tags::Tag::Var if found

package_line

Parse a package declaration, returning a Perl::Tags::Tag::Package if found.

sub_line

Parse the declaration of a subroutine, returning a Perl::Tags::Tag::Sub if found.

use_constant

Parse a use constant directive

use_line

Parse a use, require, and also a use_ok line (from Test::More). Uses a dummy tag (Perl::Tags::Tag::Recurse to do so).

label_line

Parse label declaration

`Perl::Tags::Tag`

A superclass for tags

`Perl::Tags::Tag::Package`

`Perl::Tags::Tag::Var`

`type`: v

`on_register`

        Make a tag for this variable unless we're told not to.  We
        assume that a variable is always static, unless it appears
        in a package before any sub.  (Not necessarily true, but
        it's ok for most purposes and Vim works fine even if it is
        incorrect)
            - pltags.pl comments

`Perl::Tags::Tag::Sub`

`type`: s

`on_register`

        Make a tag for this sub unless we're told not to.  We assume
        that a sub is static, unless it appears in a package.  (Not
        necessarily true, but it's ok for most purposes and Vim works
        fine even if it is incorrect)
            - pltags comments

`Perl::Tags::Tag::Constant`

`type`: c

`Perl::Tags::Tag::Label`

`type`: l

`Perl::Tags::Tag::Recurse`

`type`: dummy

`on_register`

Recurse adding this new module to the queue.

CONTRIBUTIONS

Contributions are always welcome. The repo is in git:

    http://github.com/osfameron/perl-tags

Please fork and make pull request. Maint bits available on request.

wolverian: ::PPI subclass
Ian Tegebo: patch to use File::Temp
DMITRI: patch to parse constant and label declarations
drbean: ::Naive::Spiffy and ::Naive::Lib subclasses
Alias: prodding me to make repo public
nothingmuch: ::PPI fixes
tsee: Command line interface, applying patches

AUTHOR and LICENSE

    osfameron (2006-2009) - osfameron@cpan.org
                            and contributors, as above

For support, try emailing me or grabbing me on irc #london.pm on irc.perl.org

This was originally ripped off pltags.pl, as distributed with vim and available from http://www.mscha.com/mscha.html?pltags#tools Version 2.3, 28 February 2002 Written by Michael Schaap <pltags@mscha.com>.

This is licensed under the same terms as Perl itself. (Or as Vim if you prefer).

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