[webkit-dev] Style guideline on initializing non-POD types via member initialization

[Alex Christensen]

I object.  I don’t find using { *this } in a header disorienting at all.  I think it’s better than adding many duplicate lines in each constructor and risking forgetting one.  I think if we were to remove all the 
m_attributeOwnerProxy initializers in WebKit it would add lots of duplication with little benefit. If it were a class with a default constructor we would have a high risk of forgetting a constructor somewhere.

> On Mar 20, 2019, at 9:22 AM, Simon Fraser <simon.fraser at apple.com> wrote:
> 
>> On Mar 14, 2019, at 1:06 PM, Filip Pizlo <fpizlo at apple.com> wrote:
>> 
>> I like to draw this distinction: is the initializer a constant?
>> 
>> It’s not a constant if it relies on arguments to the constructor. “This” is an argument to the constructor. 
>> 
>> It’s also not a constant if it involves reading the heap. 
>> 
>> So, like you, I would want to see this code done in the constructor. But I’m not sure that my general rule is the same as everyone’s. 
> 
> This seems like a reasonable proposal to me: only use initializers when their input is constant data.
> 
> Any objections?
> 
> Simon
> 
>> 
>> -Filip
>> 
>>> On Mar 14, 2019, at 12:59 PM, Simon Fraser <simon.fraser at apple.com> wrote:
>>> 
>>> I've seen some code recently that initializes non-POD members via initializers. For example, SVGAElement has:
>>> 
>>>  AttributeOwnerProxy m_attributeOwnerProxy { *this };
>>> 
>>> I find this a little disorientating, and would normally expect to see this in the constructor as m_attributeOwnerProxy(*this), as it makes it easier to find places to set breakpoints, and the ordering of initialization is easier to see.
>>> 
>>> Are people OK with this pattern, or should we discourage it via the style guidelines (and style checker)?
>>> 
>>> Simon
>>> 
>>> _______________________________________________
>>> webkit-dev mailing list
>>> webkit-dev at lists.webkit.org
>>> https://lists.webkit.org/mailman/listinfo/webkit-dev
> 
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> https://lists.webkit.org/mailman/listinfo/webkit-dev