Re: Implementing a plug-in mechanism

[Simon Ward]

On Thu, Mar 16, 2023 at 07:45:18AM +1300, dn via Python-list wrote:
There is a PyPi library called pluggy (not used it). I've used informal 
approaches using an ABC as a framework/reminder (see @George's 
response).


typing.Protocol is also useful here as the plugin interface can be 
defined separately not requiring inheriting from an ABC.


Simon
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Re: Debugging reason for python running unreasonably slow when adding numbers

[Roel Schroeven]

Op 14/03/2023 om 8:48 schreef Alexander Nestorov:

I have the following code:

 ...
 for i in range(151): # 150 iterations
     ...
Nothing to do with your actual question and it's probably just a small 
oversight, but still I thought it was worth a mention: that comment does 
not accurately describe the code; the code is actually doing 151 
iterations, numbered 0 up to and including 150.


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Re: Tkinter and cv2: "not responding" popup when imshow launched from tk app

[aapost]

On 3/15/23 07:37, John O'Hagan wrote:

On Tue, 2023-03-14 at 16:22 -0400, aapost wrote:

On 3/14/23 06:54, John O'Hagan wrote:


[...]





Read an alternative description of the waitKey behavior

>For example, waitKey(0) will display the window infinitely until any 
keypress (it is suitable for image display). waitKey(25) will display a 
frame and wait approximately 25 ms for a key press (suitable for 
displaying a video frame-by-frame). To remove the window, use 
cv::destroyWindow.


I went back to double check and I stand corrected on the "any keypress" 
part. Any keypress on the 'keyboard' does break the wait (as I 
incorrectly concluded and assumed only ESC did).


It is still slightly ambiguous in explaining that when using 25ms, 
keypress or not, the wait breaks at 25ms (or before that if you press a 
keyboard key). For my setup the window is stale at that point, no 
controls, just a stale frame behind the tkinter window that needs to be 
destroyed or reused.


Whether that is the exact behavior on all set-ups isn't clear, the note 
further uses the ambiguous phrasing "might".


>Note: This function should be followed by a call to cv::waitKey or 
cv::pollKey to perform GUI housekeeping tasks that are necessary to 
actually show the given image and make the window respond to mouse and 
keyboard events. Otherwise, it won’t display the image and the window 
might lock up.


It seems with the several variations, behavior varies between them, like 
one comment saying startWindowThread when using c++ and gtk allows you 
to not use waitKey (not the case here.. it seems -- changing my language 
to not misspeak, lol).


I haven't come across any examples beyond imshow running stand-alone as 
in my solution suggestion 2. But waitKey does return a keyvalue for the 
keypess to allow extending the functionality, so you can grab it, do 
something, and go right back to waiting, I haven't seen any use of this 
though.


You can also leave out reference to tkinter all together when using 
startWindowThread:


import sys
import cv2

cv2.startWindowThread()
cv2.namedWindow("W", cv2.WND_PROP_FULLSCREEN)
cv2.setWindowProperty("W", cv2.WND_PROP_FULLSCREEN, cv2.WINDOW_FULLSCREEN)
cv2.imshow("W", cv2.imread(sys.argv[1]))
while(1):
a = cv2.waitKey(0)
if a == 27:#ESC
break
#elif a == something else, do something
cv2.destroyAllWindows()
exit()

But it still blocks if integrated in to the main tkinter thread, and 
appears to use tkinter under the hood. And as tkinter is considered 
thread-unsafe, the startWindowThread would only be ok when spawned as a 
separate process like the subprocess example.


Anyway, apologies for the mistake on the any key part.

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Re: Implementing a plug-in mechanism

[Loris Bennett]

Simon Ward  writes:

> On Thu, Mar 16, 2023 at 07:45:18AM +1300, dn via Python-list wrote:
>> There is a PyPi library called pluggy (not used it). I've used
>> informal approaches using an ABC as a framework/reminder (see
>> @George's response).
>
> typing.Protocol is also useful here as the plugin interface can be
> defined separately not requiring inheriting from an ABC.

Thanks to all for the helpful suggestions.   I realise that I don't
actually need to be able to load a bunch of arbitrary plugins, but
merely to be able to override one (or, perhaps later, more) piece of
default behaviour.

Therefore I think the following very simple scheme will work for me:

  $ tree -L 3
  .
  └── myproj
  ├── __init__.py
  ├── mailer.py
  ├── main.py
  └── plugins
  └── normanmailer.py

Where main.py is

  #!/usr/bin/env python3
  # -*- coding: utf-8 -*-

  if __name__ == "__main__":

  try:
  import plugin.mailer as mailer
  print("Found plugin.mailer")
  except ModuleNotFoundError:
  import mailer
  print("Found mailer")

  m = mailer.Mailer('abc')
  m.run()

mailer.py is

  class Mailer():

  def run(self):
  print("This is a generic Mailer object!")

and plugins/normanmailer.py is

  class Mailer():

  def run(self):
  print("This is a customized Mailer object!")

This then gives me

  $ poetry run myproj\/main.py
  Found mailer
  This is a generic Mailer object!

  $ mv myproj/plugins/{norman,}mailer.py

  $ poetry run myproj\/main.py
  Found plugins.mailer
  This is a customized Mailer object!

I suspect I was using slightly incorrect/misleading terminology.  I
don't want to be able to load arbitrary functionality via plugins,
e.g. sending an email, dumping to a database, uploading to a cloud.
That would, I far as I can tell, necessitate having some mechanism to
select the functionality.

Instead I just want to modify the behaviour of a piece of fixed
functionality. e.g. sending a mail.  So am I really talking about
customisation here.

Cheers,

Loris

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ANN: Python Meeting Düsseldorf - 22.03.2023

[eGenix Team]

/This announcement is in German since it targets a local user 
group//meeting in Düsseldorf, Germany/



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März
   2023
   

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   *22.03.2023, 18:00 Uhr*
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Friday finking: IDE 'macro expansions'

[dn via Python-list]

It is a long, long, time since I've thrown one of these into the 
maelstrom of our musings.

(have the nightmares receded?)


Do you make use of your IDE's expansionist tendencies, and if-so, which 
ones?



NB this is where vi/emacs enthusiasts start chuckling (polite term for 
'insane cackling'). Hence the question's limitation to IDEs, cf 'editors'!
Also: I'm talking 'PyCharm' because of the story, but others use Codium, 
Sublime Text, etc - which presumably offer equivalent features.



Was helping a friend install PyCharm. Jumped into the Settings. Isn't it 
incredible how many there are?


Idly noted that there are two short-cut or macro-expansion types of 
facilities:

- Postfix Completion, (nothing to do with email or polish notation) and
- Live Templates (again, we're not talking about jinja2)


With both, one types an abbreviated-name and the IDE will expand it into 
appropriate code. For (LiveTemplate) example, typing compli and pressing 
Tab induces PyCharm to add the following to the program[me]:


[ ! for ! in !drop-down menu! if ! ]

It offers further typo-saving through the drop-down menu which lists a 
bunch of likely (iterable) candidates from amongst previously-written 
code. The action continues after selecting from the menu, by inviting 
completion of the other ("!") placeholders, in-turn.



I haven't made use of such a tool, to-date - OK, yes, I have practised a 
high typing-speed (and accuracy). Puff, puff...


Also, at the time, I'm thinking in 'code', rather than about what tool 
might implement said ideas.



Do you make use of such expansionist-tendencies?

Do you make use of other powerful features within the IDE, or are its 
editor functionalities employed at pretty-much the NotePad level?




Web.Refs:
https://www.jetbrains.com/help/pycharm/settings-postfix-completion.html
https://www.jetbrains.com/help/pycharm/using-live-templates.html#live_templates_types
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Re: Friday finking: IDE 'macro expansions'

[Mats Wichmann]

On 3/16/23 16:55, dn via Python-list wrote:
It is a long, long, time since I've thrown one of these into the 
maelstrom of our musings.

(have the nightmares receded?)


Do you make use of your IDE's expansionist tendencies, and if-so, which 
ones?



NB this is where vi/emacs enthusiasts start chuckling (polite term for 
'insane cackling'). Hence the question's limitation to IDEs, cf 'editors'!
Also: I'm talking 'PyCharm' because of the story, but others use Codium, 
Sublime Text, etc - which presumably offer equivalent features.



Was helping a friend install PyCharm. Jumped into the Settings. Isn't it 
incredible how many there are?


Idly noted that there are two short-cut or macro-expansion types of 
facilities:

- Postfix Completion, (nothing to do with email or polish notation) and
- Live Templates (again, we're not talking about jinja2)


With both, one types an abbreviated-name and the IDE will expand it into 
appropriate code. For (LiveTemplate) example, typing compli and pressing 
Tab induces PyCharm to add the following to the program[me]:


     [ ! for ! in !drop-down menu! if ! ]

It offers further typo-saving through the drop-down menu which lists a 
bunch of likely (iterable) candidates from amongst previously-written 
code. The action continues after selecting from the menu, by inviting 
completion of the other ("!") placeholders, in-turn.



I haven't made use of such a tool, to-date - OK, yes, I have practised a 
high typing-speed (and accuracy). Puff, puff...


Also, at the time, I'm thinking in 'code', rather than about what tool 
might implement said ideas.



Do you make use of such expansionist-tendencies?

Do you make use of other powerful features within the IDE, or are its 
editor functionalities employed at pretty-much the NotePad level?


Not sure the purpose of the "survey" but - no, I don't use these.  IDEs 
are incredible things, but you need to invest yourself completely in 
them, basically live in them, or there's not that much payback. There's 
just too much to remember, and honestly, too much mouse movement needed, 
especially if you have a big screen. In the PyCharm case, the startup 
time is incredibly slow, so, since I don't "live in it", I don't use it 
much any more - there are some things it does superbly, but it's such a 
cost to fire it up just for those I pretty much don't bother any more.


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Re: Friday finking: IDE 'macro expansions'

[Thomas Passin]

On 3/16/2023 6:55 PM, dn via Python-list wrote:
It is a long, long, time since I've thrown one of these into the 
maelstrom of our musings.

(have the nightmares receded?)


Do you make use of your IDE's expansionist tendencies, and if-so, which 
ones?



NB this is where vi/emacs enthusiasts start chuckling (polite term for 
'insane cackling'). Hence the question's limitation to IDEs, cf 'editors'!
Also: I'm talking 'PyCharm' because of the story, but others use Codium, 
Sublime Text, etc - which presumably offer equivalent features.



Was helping a friend install PyCharm. Jumped into the Settings. Isn't it 
incredible how many there are?


Idly noted that there are two short-cut or macro-expansion types of 
facilities:

- Postfix Completion, (nothing to do with email or polish notation) and
- Live Templates (again, we're not talking about jinja2)


With both, one types an abbreviated-name and the IDE will expand it into 
appropriate code. For (LiveTemplate) example, typing compli and pressing 
Tab induces PyCharm to add the following to the program[me]:


     [ ! for ! in !drop-down menu! if ! ]

It offers further typo-saving through the drop-down menu which lists a 
bunch of likely (iterable) candidates from amongst previously-written 
code. The action continues after selecting from the menu, by inviting 
completion of the other ("!") placeholders, in-turn.



I haven't made use of such a tool, to-date - OK, yes, I have practised a 
high typing-speed (and accuracy). Puff, puff...


Also, at the time, I'm thinking in 'code', rather than about what tool 
might implement said ideas.



Do you make use of such expansionist-tendencies?

Do you make use of other powerful features within the IDE, or are its 
editor functionalities employed at pretty-much the NotePad level?


In general, I don't like a lot of popups and code completions, so I tend 
to avoid them.  I don't even like automatic parens or brace insertion. 
They distract me, and often put the cursor somewhere I don't want it.


Of course, for Python code I do like automatic indentation after a 
colon: if the cursor ends up in the right place, then I'm happy.


If I'm using a plain editor, then I usually like EditPlus.  It's not 
free but the cost is low and it's well worth it (but Windows only).  It 
knows about file types, and can do various insertions and completions if 
you want (as I said, I mostly don't).  I also use Notepad++, but I more 
often go with EditPlus.


What I find more useful is matching brackets/parens/braces.  Not 
inserting them but highlighting or (better) jumping to the matching one 
when asked.


Otherwise I'm usually working in the Leo Editor, which is hard to 
explain in a few words but is a real gift, especially for Python 
programmers.  It does have an abbreviation capability that I use a 
little, but so far mostly for inserting symbols like math and Greek 
letters.  Leo is written in Python (with a Qt GUI) and you can easily 
get access to all its internals, so once you learn something about how 
it works, you can create scripts to do almost anything you want.


The Leo Editor is an MIT-licensed project on GitHub (I know I sound very 
positive but despite that, it's not my project; it really can grow on 
you - if you are willing to climb the learning curve).


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Re: Friday finking: IDE 'macro expansions'

[2QdxY4RzWzUUiLuE]

On 2023-03-17 at 11:55:38 +1300,
dn via Python-list  wrote:

> Do you make use of your IDE's expansionist tendencies, and if-so, which
> ones?

Expansionist tendencies.  Nice phrase.  :-)

> NB this is where vi/emacs enthusiasts start chuckling (polite term for
> 'insane cackling') ...

Long time (since the 1980s, when you had to edit config.h and compile it
yourself) insane emacs enthusiast and "Unix is my IDE" claimant here.  I
used one language that required a special editor because the "source
code" was a semi-compiled byte stream instead of ASCII.  A coworker once
awarded me a black belt in vi for knowing how to indent and unindent
code.

They made me write in Java at my last job; that language encourages IDEs
beause they deny that the underlying OS and tools exist at all.  I used
to say that some of my coworkers weren't writing Java, they were writing
IntelliJ.

Anyway, the short answer to your question is no.

I think the main reason is that there are/were too many editors in too
many contexts to start depending on such features.  What happens if I'm
editing on a target box instead of my desktop?  What if I'm helping a
coworker, and they use a different editor (different tools for different
programmers)?

> I haven't made use of such a tool, to-date - OK, yes, I have practised a
> high typing-speed (and accuracy). Puff, puff...

I, too, type relatively quickly, which definitely relieves some of the
appeal.  Saving a few keystrokes isn't worth the extra congnitive load
to remember how to use those features.  And by the time I edit the
template, it's more keystrokes (and usually cursor motion and
placeholder deletion keystrokes not related to the programming task at
hand) than if I had typed the full code in the first place.

> Also, at the time, I'm thinking in 'code', rather than about what tool might
> implement said ideas.

Exactly.  Any excursion away from the programming language and the
programming task at hand is disruptive.

I did finally train myself to use Emacs' dabbrev-expand function, which
completes the current "word" according to the previous occurrance of
that word, which lets me use longer identifiers without having to type
them out or copy/paste them.  That said, I often find myself typing
stuff out anyway, again because any deviation from writing code is a
deviation from writing code.
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Re: Friday finking: IDE 'macro expansions'

[Grant Edwards]

On 2023-03-16, Thomas Passin  wrote:

> In general, I don't like a lot of popups and code completions, so I
> tend to avoid them.  I don't even like automatic parens or brace
> insertion.

I _hate_ it when the "editor" decides to insert stuff I didn't
type. There's an html editor I use occasionally that auto-inserts the
closing tag when you type an opening tag. It's, always, 100% of the
time, wrong. Either the tag ends up in the wrong place, or it's a
duplicate because there was already a closing tag.

> They distract me, and often put the cursor somewhere I don't want it.

Maybe it matters how good a typist you are, but I don't really
concentrate that hard on watching the letters show up on the screen,
so any sort of "IDE know better than you do" stuff tends to trip me
up.

> Of course, for Python code I do like automatic indentation after a 
> colon: if the cursor ends up in the right place, then I'm happy.

Yep, I do allow emacs to do auto indent.

> If I'm using a plain editor, then I usually like EditPlus.  It's not
> free but the cost is low and it's well worth it (but Windows only).
> It knows about file types, and can do various insertions and
> completions if you want (as I said, I mostly don't).  I also use
> Notepad++, but I more often go with EditPlus.
>
> What I find more useful is matching brackets/parens/braces.  Not 
> inserting them but highlighting or (better) jumping to the matching one 
> when asked.

Same here.



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