Jiří Zárevúcky <zarevucky.j...@gmail.com> writes:
> On 08/01/2009 04:36 PM, Łukasz Pankowski wrote:
>> Hello
>>
>> According to the Vala tutorial
>>
>> "Finally Vala has a mechanism called Type Inference, whereby a local
>> variable may be defined using var instead of giving a type, so long as
>> it is unambiguous what type is meant."
>>
>> Type Interface works great for owned variables (for example in
>> declaration of variable b below) but not for weak variable (neither
>> declaration of c2 nor c3 works).
>>
>> I would prefer just "weak" (as in declaration of c2) as shorter, but
>> maybe "weak var" would be more readable/discoverable?
>>
>> What do you think about the idea? Would this be hard to implement?
>>
>>
>> class Foo {}
>>
>> void main ()
>> {
>> // var for short
>> Foo a = new Foo();
>> var b = new Foo();
>>
>> // no `weak' for short
>> weak Foo c1 = a;
>> weak c2 = a; // syntax error
>> weak var c3 = a; // syntax error
>> }
>>
>
> I and Julien proposed that, but juergbi closed it as WONTFIX without
> discussion.
> Maybe if more people express their opinion, we could change his mind?
>
> See this bug: http://bugzilla.gnome.org/show_bug.cgi?id=586486
Another performance related usage of the weak variables (apart from one
you mentioned in the bug comment #3) is that properties return weak
variables so the values are copied unless assigned to the weak variable
(as in the code below) and here "weak t = a.str" shortcut would also be
convenient.
class Foo {
public string str { get; set; }
}
void main ()
{
Foo a = new Foo();
// uses g_strdup to duplicate the string
var s = a.str;
// no duplication needed
weak string t = a.str;
}
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