On Mon, 16 Jan 2017 at 22:34 INADA Naoki <songofaca...@gmail.com> wrote:
> Hi. > > --- > This discussion is started in http://bugs.python.org/issue29259, and > there is separated issue at http://bugs.python.org/issue29260 . > But I want to see more comments, before issue 29259 is committed. > --- > > Since Python 3.6, some of C99 features are accepted in PEP 7. > "designated initializer" is one of them. > > PEP7 says "designated initializers (especially nice for type > declarations)" > > For example, issue 29259 is adding new slot named tp_fastcall in type > structure. > Without designated initializer, there are many diffs like this: > > 0, /* tp_free */ > + 0, /* tp_is_gc */ > + 0, /* tp_bases */ > + 0, /* tp_mro */ > + 0, /* tp_cache */ > + 0, /* tp_subclasses */ > + 0, /* tp_weaklist */ > + 0, /* tp_del */ > + 0, /* tp_version_tag */ > + 0, /* tp_finalize */ > + (fastternaryfunc)attrgetter_call, /* tp_fastcall */ > }; > > With designated initializer, it becomes: > > 0, /* tp_free */ > + .tp_fastcall = (fastternaryfunc)attrgetter_call, > }; > > It's readable, and easy to review. > Without designated initializer, it's difficult to find copy & paste > mistake. > (Can you find if I missed /* tp_is_gc */ line in first patch?) > > On the other hand, this syntax is C99 specific. > C++ doesn't accept this syntax, even for newest C++14. > Using this feature make it's difficult to use (subset of) C++ features > in the future. > At this point I really doubt we will ever switch to C++ so I don't think making any such theoretical transition is worth holding back cleaner code. Plus if this isn't going into a header file that some C++ extension module is going to be pulling in then third-party C++ code should be shielded from the incompatibility. > > > So, how widely can we use "designated initializer"? > Only in Modules (_asyncio uses it already)? > Or almost everywhere (Objects/ and Python/)? > I say everywhere we can (and that also means we should probably update the xx* files in Modules/). -Brett > > I want to get decision before issue 29259 is committed, because it > will add many "0, /* tp_xxx */" > > Regards, > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > https://mail.python.org/mailman/options/python-dev/brett%40python.org >
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