gcc complained that a variable might be used uninitialized, which is
true. If NULL is passed, all code gets executed with an
uninitialized variable which is an error in almost every case.
Since python itself never passes NULL, only a real error in
other c code could trigger the assert.

scope-entry as a variable. This means that
analyse_attribute expects to find a pointer to
a member of the c-object struct.
This is not the case for members, so we need a
special case.

Fixes

cdef int a, b
cdef int *foo = &a if a else &b

so the generated c files don't depend on the version of python used to run Cython

slots for new pyton versions are not emitted
for older versions. This stops compiler warnings.

The issue here (as pointed out by Thomas Hunger) is that once the CClass
body gets executed the class is already constructed, and its methods
are actual methods not functions (as in Python).

The CClassScope now returns a utility function on lookup of "classmethod"
that creates a class method out of a method (rather than out of a function).
When added to the type dictionary, the result is exactly the same as setting
the METH_CLASS flag.

a direct change of a classes tp_dict instead
of SetAttr if assignment code is executed in
a class body.
To tell the code generator that we have a class
entry, entry has a new attribute "is_member".

because the class-body code is exectuted at module-init time.

use 'with GIL' instead of 'withGIL' to avoid introducing a non-Python keyword and to support later extension for other contexts

use 'with GIL' instead of 'withGIL' to avoid introducing a non-Python keyword and to support later extension for other contexts

This is so mutating inplace operations can be detected safely.