On 03.05.2018 20:11, Ryan Gonzalez wrote:
On May 3, 2018 11:56:24 AM MRAB <pyt...@mrabarnett.plus.com> wrote:
On 2018-05-03 13:24, Steve Holden wrote:
On Thu, May 3, 2018 at 12:12 AM, Ivan Pozdeev via Python-Dev
<python-dev@python.org <mailto:python-dev@python.org>> wrote:
On 03.05.2018 1:01, Antoine Pitrou wrote:
On Wed, 2 May 2018 22:54:04 +0100
Paul Moore <p.f.mo...@gmail.com
<mailto:p.f.mo...@gmail.com>> wrote:
On 2 May 2018 at 22:37, Antoine Pitrou <solip...@pitrou.net
<mailto:solip...@pitrou.net>> wrote:
To elaborate a bit: the OP, while angry, produced
both a
detailed
analysis *and* a PR. It's normal to be angry when an
advertised
feature doesn't work and it makes you lose hours of
work
(or, even,
forces you to a wholesale redesign). Producing a
detailed analysis and a
PR is more than most people will ever do.
His *other* email seems reasonable, and warrants a
response,
yes. But
are we to take the suggestion made here (to drop tkinter)
seriously,
based on the fact that there's a (rare - at least it
appears
that the
many IDLE users haven't hit it yet) race condition that
causes a crash
in Python 2.7? (It appears that the problem doesn't happen
in the
python.org <http://python.org> 3.x builds, if I understand
the description of the issue).
In 3.x, Tkinter+threads is broken too, albeit in a different way --
see https://bugs.python.org/issue33412
<https://bugs.python.org/issue33412> (this should've been the 2nd
link in the initial message, sorry for the mix-up).
The observation in that issue that tkinter and threads should be
handled in specific ways is certainly a given for old hands, who have
long put the GUI code in one thread with one or more concurrent worker
threads typically communicating through queues. But I haven't built
anything like that recently, so I couldn't say how helpful the current
documenation might be.
Interacting with the GUI only in the main thread is something that I've
had to do in other languages (it is/was the recommended practice), so I
naturally do the same with Python and tkinter. It's also easier to
reason about because you don't get elements of the GUI changing
unexpectedly.
To add to this, most GUI frameworks disallow modifications outside the
main thread altogether. IIRC both GTK+ and Qt require this, or else
it's undefined altogether.
You still need some facility (*cough*SendMessage*cough*) to send update
commands to the GUI (the model->view link in MVC, presenter->view in MVP).
Who and how specifically carries out these commands is unimportant, an
implementation detail.
Every GUI has an event/message queue exactly for that, that other
threads can sent work requests into:
https://doc.qt.io/qt-5.10/qcoreapplication.html#postEvent ,
https://developer.gnome.org/gdk3/stable/gdk3-Threads.html#gdk3-Threads.description
,
https://en.wikipedia.org/wiki/Event_dispatching_thread#Submitting_user_code_to_the_EDT
, the aforementioned WinAPI's SendMessage() and PostMessage() just to
name a few.
Tcl/Tk, being arguably the oldest usable GUI toolkit in existence, has
an event queue likewise but doesn't provide a complete event loop
implementation, only the building blocks for it. Tkinter fills that gap
with its `tk.mainloop()`.
It fails to provide a working means to send work into it though. Having
to use a second, duplicating event queue and poll it (=busy loop)
instead is an obvious crutch.
[snip]
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Ryan (ライアン)
Yoko Shimomura, ryo (supercell/EGOIST), Hiroyuki Sawano >> everyone else
https://refi64.com/
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Regards,
Ivan
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