Sample block tag using framework

Here's an example of a block tag (mt:Blogs) using the common iterator method described in Proposal:Iterator template tag consistency:

sub _hdlr_blogs {
    my($ctx, $args, $cond) = @_;
    my (%terms, %args);

    $ctx->set_blog_load_context($args, \%terms, \%args, 'id')
        or return $ctx->error($ctx->errstr);

    my $builder = $ctx->stash('builder');
    my $tokens = $ctx->stash('tokens');

    local $ctx->{__stash}{entries} = undef
        if $args->{ignore_archive_context};
    local $ctx->{current_timestamp} = undef
        if $args->{ignore_archive_context};
    local $ctx->{current_timestamp_end} = undef
        if $args->{ignore_archive_context};
    local $ctx->{__stash}{category} = undef
        if $args->{ignore_archive_context};
    local $ctx->{__stash}{archive_category} = undef
        if $args->{ignore_archive_context};

    require MT::Blog;
    $args{'sort'} = 'name';
    $args{direction} = 'ascend';

    my $iter = MT::Blog->load_iter(\%terms, \%args);
    my $vars = $ctx->{__stash}{vars} ||= {};

    return $ctx->block_tag_iterator({
        iterator   => $iter,
        attributes => $args,
        condition  => $cond,
        prerun     => sub {
            my ($ctx, $args, $obj, $next) = @_;
            $ctx->{__stash}{blog}    = $obj;
            $ctx->{__stash}{blog_id} = $obj->id;
            $ctx;
        },
        postrun    => sub { },
        skip       => sub { },
    });
}