[pmwiki-users] new page attribute

[Patrick R. Michaud]

On Mon, Sep 25, 2006 at 10:02:15PM -0400, Henrik Bechmann wrote:
> Not good...
> >However, if we're just displaying the summary field, it's far more
> >efficient to simply write
> >
> >    {$:Summary}
> >  
> But if I don't get to test it, I don't get the chance to substitute 
> something else (eg description or title) if the summary is absent...

One could write a custom page variable to handle the substitution
exactly as you wish:

    $FmtPV['$Summary'] = 'Summary($pn)';

    function Summary($pagename) {
      $v = PageVar($pagename, '$:Summary');
      if (!$v) $v = PageVar($pagename, '$Description');
      if (!$v) $v = PageVar($pagename, '$Title');
      return $v;
    }

This causes {$Summary} to return {$:Summary} if it's defined,
otherwise it returns the page description, otherwise it returns
the title.

We can also add a custom 'summary' condition

    $Conditions['summary'] = '(boolean)PageVar($pagename, "$:Summary")'

and then use (:if summary:) to test for the summary definition.

> >>$FmtPV['$Summary'] = '$page["summary"]';
> >>    
> >Well, you can do that, but if you're setting it up as a separate
> >input field, it's not really a page text variable or a "property"
> >in the sense that we've been using that word here.  ("Properties"
> >are values defined in the markup.)  It's just another attribute of
> >the page that is being managed as a separate field.
> >  
> It seems to me, in light of what you've said, that this would be the 
> simplest option for my requirements. Presuming there is a legitimate way 
> of adding such an attribute to a page, and managing it.

Adding such an attribute isn't too bad; you'll want a custom
entry in $EditFunctions that manages the attribute.

Pm