Re: Conditional filtering

On 10/20/05, Andy Wardley <abw-Bb0B45GnRERAfugRpC6u6w@xxxxxxxxxxxxxxxx> wrote:
> Nik Clayton wrote:
> >     [% msg | html | html_line_break | catch_all %]
> >
> > Which should work, but doesn't strike me as being terribly elegant.
>
> You can make that more elegant with a MACRO:
>
>   [% MACRO message(m) GET m | html | html_line_break | catch_all %]
>
>   [% message(msg) %]
>

Ah.  I didn't mean the elegance of the appearance in the template, I
meant the elegance of having to define my own filter which wrapped a
collection of other filters.

So does that mean that it's not easy, within the Template language, to
conditionally select from multiple filters?

I've been trying the approach of defining my own filter which wraps a
collection of others, and not getting terribly far.  I've added my
catch_all_filter to the FILTERS list and it's being called.  I thought
I'd try and get one existing filter working first, the previously
mentioned Template::Plugin::Clickable.  Using the Badger book as my
guide, I came up with:

sub catch_all_filter {
    my $text = shift;
    $template ||= get_template();

    # One filter for the time being, will eventually iterate over a list of
    # [ $filter_name, $is_dynamic ]
    my $filter_name = 'Template::Plugin::Clickable';

    eval "use $filter_name";
    if(! $@) {
      my $s = $filter_name->filter_factory($template->context());

      $text = $s->($text);
    }
    return $text;
}

which, when run, leaves a "Not a CODE reference" error in the logs,
referring to the "$text = $s->($text);" line.

Am I on the right track, or is this sort of approach doomed to
failure?  It did occur to me that I'm reinventing code that
Template::Filters already has, which is probably not a good thing...

N