I am ok with the where applying on an explicit default argument. But
I understand the implicit
default argument as the way to manifest the absence of that argument.
So that doest not make much sense to test if that value is conform to
the where constraint
because in essence there is no value to test.
On Thursday, July 15, 2010, jn...@jnthn.net via RT
<perl6-bugs-follo...@perl.org> wrote:
> On Wed Jul 14 16:25:26 2010, cognominal wrote:
>> Here, the where clause is applied to the default value, the undefined
>> type Any
>> and results in an error.
>>
>> $ perl6
>> > sub a(Range $r? where {$r.min >= 0} ) {}; a()
>> Type objects are abstract and have no attributes, but you tried to
>> access $!min
>> >
>>
>
> Rejecting this one - it's behaving as expected. From #perl6:
>
> 12:31 <@jnthn> Opinions on
> http://rt.perl.org/rt3/Ticket/Display.html?id=76514 ?
> 12:31 <@jnthn> Tempted to reject as "not a bug".
> 12:31 <@jnthn> Default values should be subject to checking too.
> 12:32 <@moritz_> +1
> 12:32 <@jnthn> (and sticking in the Range type object is just a kinda
> default value)
> 12:32 <@moritz_> the correct solution is to supply a custom default
> value, of course
> 12:36 <@jnthn> OK, thanks. :-)
>
> Essentially, if you're going to put constraints on a parameter or
> variable, then those constraints should always apply. You could:
>
> * Supply a default value
>
> * Tweak the constraint to allow !$r.defined || $r.min >= 0
>
> To resolve this.
>
> Thanks,
>
> Jonathan
>
--
cognominal stef
