__nonzero__ does not work

[Johan Råde]

I can not add the special method __nonzero__ to my wrapped classes.
Here is a test that shows the problem.

(Adding __len__ and __getitem__ works, but __nonzero__ does not.
I'm using Python 2.7 and PyBindGen 0.15.0.)

----- Test.h: -----

class X0 {
public:
    operator bool() const { return false; }
};

class X1 {
public:
    bool __nonzero__() const { return false; }
};

class X2 {
public:
    bool nonZero() const { return false; }
};

class X3 {};

inline bool __nonzero__(const X3&) { return false; }

class X4 {};

inline bool nonZero(const X4&) { return false; }

----- TestBindings.py -----

import pybindgen
param = pybindgen.param
retval = pybindgen.retval

Test = pybindgen.Module('Test')
Test.add_include('"Test.h"')

X0 = Test.add_class('X0')
X0.add_constructor([])
X0.add_method('operator bool', retval('bool'), [], custom_name = '__nonzero__')

X1 = Test.add_class('X1')
X1.add_constructor([])
X1.add_method('__nonzero__', retval('bool'), [])

X2 = Test.add_class('X2')
X2.add_constructor([])
X2.add_method('nonZero', retval('bool'), [], custom_name = '__nonzero__')

X3 = Test.add_class('X3')
X3.add_constructor([])
X3.add_function_as_method('__nonzero__', retval('bool'), [param('const X3&', 'x3')])

X4 = Test.add_class('X4')
X4.add_constructor([])
X4.add_function_as_method('nonZero', retval('bool'), [param('const X4&', 'x4')], custom_name = '__nonzero__')

----- Main.py -----

import Test
print bool(Test.X0())
print bool(Test.X1())
print bool(Test.X2())
print bool(Test.X3())
print bool(Test.X4())

----- Expected result -----

Main.py produces the output

False
False
False
False
False

----- Observed result -----

Main.py produces the output

True
True
True
True
True

[Johan Råde (johan-rade)]

I took a look at the C code generated by PyBindGen.
(Fortunately PyBindGen generated exceptionally readable code.)
There I could see that my __nonzero__ method was added to the tp_methods member of the type object.
It should have been added as the nb_nonzero member of the tp_as_number member of the type object; see
http://docs.python.org/c-api/typeobj.html#number-object-structures

So it seems that either I have added __nonzero__ the wrong way, or this is a PyBindGen bug.

[Gustavo Carneiro (gjc)]

These are simply not regular methods. There's a generic pybindgen support for normal methods, but these are special methods that require specific handling for each one. This is a case of a feature not implemented yet.

[Johan Råde (johan-rade)]

Is there a list anywhere in the docs of important features that are not implemented yet?

[Gustavo Carneiro (gjc)]

Incomplete list here: http://code.google.com/p/pybindgen/wiki/Features

I should add: by default, assume that __special_method__ is not properly supported, until evidence to the contrary.

Sorry, blame python, not me, for not making things easier :P