py3 making __nonzero__ an alias for __bool__ in rings folder

[fchapoton]

as a step to py3

part of #16076

here only in the rings folder

Component: python3

Author: Frédéric Chapoton

Branch/Commit: b279834

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/21887

[fchapoton]

New commits:

1eb9e08

making `__nonzero__` an alias for `__bool__` in rings folder

[fchapoton]

Commit: 1eb9e08

[fchapoton]

Branch: u/chapoton/21887

[jdemeyer]

comment:2

This is not needed for Cython extension types. Cython understands both special methods __nonzero__ and __bool__.

There is one potential caveat: if you really need __nonzero__ and __bool__ non-special methods (that is, you really need obj.__bool__ and not just bool(obj) or not obj), your trick might be needed.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

e62142d

trac 21887 one missing case

[sagetrac-git]

Changed commit from 1eb9e08 to e62142d

[fchapoton]

comment:4

So should I refrain to make changes to any pyx or pxi files ?

I would prefer to have something uniform, even if it is not necessary. Does it do any harm to do that also in pyx files ?

[jdemeyer]

comment:5

Replying to @fchapoton:

Does it do any harm to do that also in pyx files ?

There is no obvious harm, apart from code bloat.

[jdemeyer]

comment:6

OK, I actually tested it and it doesn't work...

/usr/local/src/sage-config/src/sage/rings/complex_number.pyx in init sage.rings.complex_number (/usr/local/src/sage-config/src/build/cythonized/sage/rings/complex_number.c:25899)()
    860                                       imag_string, digit_precision_bound)
    861 
    862     def __bool__(self):
    863         """
    864         Return ``True`` if ``self`` is not zero. This is an internal function;
    865         use :meth:`is_zero()` instead.
    866 
    867         EXAMPLES::
    868 
    869             sage: z = 1 + CC(I)
    870             sage: z.is_zero()
    871             False
    872         """
    873         return not (mpfr_zero_p(self.__re) and mpfr_zero_p(self.__im))
    874 
--> 875     __nonzero__ =__bool__
        global __nonzero__ = undefined
        global __bool__ = undefined
    876 
    877     def prec(self):
    878         """
    879         Return precision of this complex number.
    880 
    881         EXAMPLES::
    882 
    883             sage: i = ComplexField(2000).0
    884             sage: i.prec()
    885             2000
    886         """
    887         return self._parent.prec()
    888 
    889     def real(self):
    890         """

NameError: name '__bool__' is not defined

I guess Cython extension types don't allow such assignment of special methods.

[jdemeyer]

comment:7

To fix code like obj.__nonzero__() (for example in src/sage/rings/complex_interval.pyx), I would just use bool(obj). That should "just work" in Python 2 and Python 3.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

41d63ab

trac 21887 undoing alias of `__nonzero__` in pyx files

[sagetrac-git]

Changed commit from e62142d to 41d63ab

[jdemeyer]

comment:9

.pxi files should be treated just like .pyx files.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

28728df

trac 21887 undo aliasing in pxi files too

[sagetrac-git]

Changed commit from 41d63ab to 28728df

[sagetrac-git]

Changed commit from 28728df to b279834

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

b279834

trac 21887 some forgotten cases

[fchapoton]

comment:12

ok, works now, green bot, setting to needs_review

[jdemeyer]

Reviewer: Jeroen Demeyer

[vbraun]

Changed branch from u/chapoton/21887 to b279834