[PyQt] Floats accepted for C++ ints?

[Florian Bruhin]

* Phil Thompson <phil at riverbankcomputing.com> [2016-07-05 18:33:37 +0100]:
> On 5 Jul 2016, at 6:22 pm, Florian Bruhin <me at the-compiler.org> wrote:
> > 
> > I've noticed Python floats are accepted when a C++ int is expected,
> > and simply truncated:
> > 
> > 	>>> from PyQt5.QtCore import QRect
> > 	>>> QRect(0.5, 0.5, 0.5, 0.5)
> > 	PyQt5.QtCore.QRect()
> > 	>>> QRect(1.5, 1.5, 1.5, 1.5)
> > 	PyQt5.QtCore.QRect(1, 1, 1, 1)
> > 
> > Is this intended behaviour? I'd have expected to raise a TypeError
> > (or, if anything, accept floats where .is_integer() is true)
> 
> It's standard Python behaviour. Floats implement __int__().

They also implement __str__, yet I obviously can't use them where Qt
expects a QString ;)

Isn't __int__ just there to customize what should happen when using
int(), just like __str__ is for str()?

float is not a subclass of int (i.e. isinstance(1.5, int) == False),
which is why this not raising a TypeError confuses me.

Florian

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