[Interest] QVariant compare operator

[Thiago Macieira]

On Sunday, 19 April 2020 08:05:05 -03 André Pönitz wrote:
> > We can't do that right now because we can't rely on C++20. In fact, no
> > current compiler supports the spaceship operator. So that has to be Qt 7.
> 
> How comes the spaceship operator comes into play here?
> 
> It's syntactical sugar and in some cases an optimization, but has no
> concepual powers exceeding those of operator<().

It's an optimisation: the QMetaType vtable for the type can contain a single 
entry (spaceship) instead of one for equality and one for ordering. In 
addition, we can determine how the element can compare by inspecting the 
return type.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel System Software Products