On 10/24/2016 2:14 PM, jlada...@itu.edu wrote:
After reading this rather vague thread...
https://groups.google.com/forum/#!topic/comp.lang.python/FVnTe2i0UTY
... I find myself asking why Python doesn't include a standard,
non-blocking keyboard input function. I have often wanted one
myself. The only way that I've ever achieved this behavior is:
1) by restricting the user to pressing Ctrl-C while the program is
running, and catching a KeyboardInterrupt; or
2) loading a heavyweight GUI like wxPython or PyQt, and using its
event loop to intercept keyboard events.
Or load the lighter weight cross-platform tkinter GUI that comes with
Python. One can either make the GUI invisible or use at least a Text or
Entry widget instead of the OS console. The text widget comes with
numerous key and mouse bindings, including the generic "Display glyph in
response to press of graphics key".
Either way, if one wants to do a prolonged computation, one must either
put it another thread or split it into chunks of limited duration, such
50 milleseconds (1/20 second), with breaks in between that allow user
input handling.
I gather that non-blocking keyboard input functions aren't the
easiest thing to implement. They seem to depend on the operating
system. Still, ease of use is a primary goal of Python, and the need
for this feature must be common.
What is not common today is to only want asynchronous keypress handing
without the use of any GUI widget (other than the OS-supplied console).
--
Terry Jan Reedy
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