On 06/12/2018 19:53, chrispitude@gmail.com via RT wrote:
Show quoted text> Thu Dec 06 13:53:27 2018: Request 127945 was acted upon.
> Transaction: Ticket created by chrispitude@gmail.com
> Queue: XML-Twig
> Subject: Allow handlers to stack
> Broken in: 3.52
> Severity: Wishlist
> Owner: MIROD
> Requestors: chrispitude@gmail.com
> Status: new
> Ticket <URL:
https://rt.cpan.org/Ticket/Display.html?id=127945 >
>
>
> It would be nice to allow handlers to "stack" when there are collisions. There are many times where the handlers intersect due to orthogonal but overlapping work that needs to be done.
>
> For example, both handlers should be invoked for <orange/> here:
>
> 'apple|orange|pear' => sub { $_->set_att('fruit', 1); },
> 'red|orange|yellow' => sub { $_->set_att('color', 2); },
Handlers do stack, as long as they return a true value... except in this
case.
In this case, since the triggers include '|', they are expanded, and in
effect the code is equivalent to this:
apple => sub { $_->set_att('fruit', 1); },
orange => sub { $_->set_att('fruit', 1); },
pear => sub { $_->set_att('fruit', 1); },
red => sub { $_->set_att('color', 2); },
orange => sub { $_->set_att('color', 2); },
yellow => sub { $_->set_att('color', 2); }
Since the second "orange" handler has the exact same trigger as the
first one, it replaces it. This is by design, so you can replace a handler.
Changing this would require quite a bit of rework of the internals of
the module, a (small) speed penalty for everyone, and likely a
convoluted way to tell the module to add the handler and not to replace it.
One (ugly?) way to get this to work without changing the module is to
have the second "orange" trigger be different from the first one, while
still triggering for all the orange elements, by doing something like this:
'red|orange[!@dummy]|yellow' => sub { $_->set_att('color', 2); }
Here there is no overlap, both handlers are kept, and trigger for all
orange elements (I am assuming no orange element will ever have a
"dummy" attribute).
