Re: custom vmethods

On 2016-02-24 14:17, Tom Molesworth wrote:
> Hi Dave,
>
> On 24/02/16 14:07, Dave Howorth wrote:
>> On 2016-02-24 13:01, Tom Molesworth wrote:
>>> On 24/02/16 12:44, Dave Howorth wrote:
>>>> I'm trying to define a custom vmethod but not succeeding.
>>>>
>>>> I tried using the way described in the manual and also by calling
>>>> define_vmethod. Both ways appear to have set up methods in the
>>>> Template::Stash::SCALAR_OPS hashref but neither of them appears to
>>>> work, even with a very simple body. Any clues to what I'm doing wrong
>>>> gratefully received!
>>>>
>>>> In the perl:
>>>>
>>>> use Template::Stash;
>>>> $Template::Stash::SCALAR_OPS->{uniprot_is_obsolete} =
>>>>     sub {
>>>>         return 42;
>>>>     };
>>>>
>>>> sub forty_two { return 42; }
>>>> Template::Stash->define_vmethod('scalar', 'forty_two', &forty_two);
>>>>
>>>> warn join ' ', keys %$Template::Stash::SCALAR_OPS, "\n";
>>>
>>> Those look fine - are you sure that [% representative %] is defined as a
>>> scalar rather than a hashref/arrayref/object?
>>
>> representative is an object. An object is a scalar. If I replace the
>> definition of x in your test by x => sub {123} the test still passes.
>>
>> More to the point, representative.defined returns 1 and has the same
>> code (apart from the value of the numerical constant) as forty_two,
>> which doesn't return 42!
>
> So it's a blessed hashref? If so, I'd expect that to be attempting to
> look up the key rather than calling scalar ops. Put those custom
> definitions in the 'hash' rather than 'scalar' ops definition and things
> should start working, although that's going to affect any hash lookups
> that use obj.key rather than obj.item(key).

Hi Tom,

It's TT2's strange worldview again. But thanks for the hint. I used a 
dummy scalar and passed the object as an extra argument. It looks clunky 
but at least it's obvious what's going on.

Thanks again for the help,
Dave

> See updated test attached.
>
> cheers,
>
> Tom
>