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Python3 curses behavior

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  Python3 curses behavior Vlasov Vitaly <vnigtha@gmail.com> - 2013-02-09 03:23 -0800
    Re: Python3 curses behavior Chris Angelico <rosuav@gmail.com> - 2013-02-09 22:28 +1100
      Re: Python3 curses behavior Vlasov Vitaly <vnigtha@gmail.com> - 2013-02-09 04:38 -0800
      Re: Python3 curses behavior Vlasov Vitaly <vnigtha@gmail.com> - 2013-02-09 04:38 -0800
    Re: Python3 curses behavior Terry Reedy <tjreedy@udel.edu> - 2013-02-09 14:22 -0500
      Re: Python3 curses behavior Vlasov Vitaly <vnigtha@gmail.com> - 2013-02-10 14:06 -0800
        Re: Python3 curses behavior Dan Stromberg <drsalists@gmail.com> - 2013-02-11 15:53 -0800
      Re: Python3 curses behavior Vlasov Vitaly <vnigtha@gmail.com> - 2013-02-10 14:06 -0800

#38507 — Python3 curses behavior

Hello.

I found strange behavior of curses module, that i can't understand. I initialize screen with curses.initscr(), then i create subwin of screen with screen.subwin(my_subwin_sizes). After that i fill subwin with my_char in for-loop. On last char in last line subwin.addch() raises exception.

This is my problem. Why? How to fix it?

(If i will ignore exception, then last char will be displayed)

Here simple example:
http://pastebin.com/SjyMsHZB

Thank You!

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#38510

On Sat, Feb 9, 2013 at 10:23 PM, Vlasov Vitaly <vnigtha@gmail.com> wrote:
> Hello.
>
> I found strange behavior of curses module, that i can't understand. I initialize screen with curses.initscr(), then i create subwin of screen with screen.subwin(my_subwin_sizes). After that i fill subwin with my_char in for-loop. On last char in last line subwin.addch() raises exception.
>
> This is my problem. Why? How to fix it?
>
> (If i will ignore exception, then last char will be displayed)
>
> Here simple example:
> http://pastebin.com/SjyMsHZB

What exception is being raised? That's kinda the most important part here :)

ChrisA

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#38513

суббота, 9 февраля 2013 г., 15:28:51 UTC+4 пользователь Chris Angelico написал:
> On Sat, Feb 9, 2013 at 10:23 PM, Vlasov Vitaly <vnigtha@gmail.com> wrote:
> 
> > Hello.
> 
> >
> 
> > I found strange behavior of curses module, that i can't understand. I initialize screen with curses.initscr(), then i create subwin of screen with screen.subwin(my_subwin_sizes). After that i fill subwin with my_char in for-loop. On last char in last line subwin.addch() raises exception.
> 
> >
> 
> > This is my problem. Why? How to fix it?
> 
> >
> 
> > (If i will ignore exception, then last char will be displayed)
> 
> >
> 
> > Here simple example:
> 
> > http://pastebin.com/SjyMsHZB
> 
> 
> 
> What exception is being raised? That's kinda the most important part here :)
> 
> 
> 
> ChrisA

curses.error <-- all curses-related exception
Exception text: curses.error: 'addch() returned ERR'

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#38514

суббота, 9 февраля 2013 г., 15:28:51 UTC+4 пользователь Chris Angelico написал:
> On Sat, Feb 9, 2013 at 10:23 PM, Vlasov Vitaly <vnigtha@gmail.com> wrote:
> 
> > Hello.
> 
> >
> 
> > I found strange behavior of curses module, that i can't understand. I initialize screen with curses.initscr(), then i create subwin of screen with screen.subwin(my_subwin_sizes). After that i fill subwin with my_char in for-loop. On last char in last line subwin.addch() raises exception.
> 
> >
> 
> > This is my problem. Why? How to fix it?
> 
> >
> 
> > (If i will ignore exception, then last char will be displayed)
> 
> >
> 
> > Here simple example:
> 
> > http://pastebin.com/SjyMsHZB
> 
> 
> 
> What exception is being raised? That's kinda the most important part here :)
> 
> 
> 
> ChrisA

curses.error <-- all curses-related exception
Exception text: curses.error: 'addch() returned ERR'

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#38536

On 2/9/2013 6:23 AM, Vlasov Vitaly wrote:
> Hello.
>
> I found strange behavior of curses module, that i can't understand. I
> initialize screen with curses.initscr(), then i create subwin of
> screen with screen.subwin(my_subwin_sizes). After that i fill subwin
> with my_char in for-loop. On last char in last line subwin.addch()
> raises exception.

I have never used curses but I have used text screens. I suspect that 
addch moves the cursor to the position beyond where the character is 
added, but there is no such position. I remember having problems writing 
to the last char of a 24x80 screen without getting either a scroll or 
beep if scrolling was disabled.

> This is my problem. Why? How to fix it?

Perhaps this will help:
window.leaveok(yes)
If yes is 1, cursor is left where it is on update, instead of being at 
“cursor position.” This reduces cursor movement where possible. If 
possible the cursor will be made invisible.

> (If i will ignore exception, then last char will be displayed)

Otherwise, just catch the exception, as you already discovered.

> Here simple example: http://pastebin.com/SjyMsHZB

-- 
Terry Jan Reedy

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#38607

суббота, 9 февраля 2013 г., 23:22:47 UTC+4 пользователь Terry Reedy написал:
> On 2/9/2013 6:23 AM, Vlasov Vitaly wrote:
> 
> > Hello.
> 
> >
> 
> > I found strange behavior of curses module, that i can't understand. I
> 
> > initialize screen with curses.initscr(), then i create subwin of
> 
> > screen with screen.subwin(my_subwin_sizes). After that i fill subwin
> 
> > with my_char in for-loop. On last char in last line subwin.addch()
> 
> > raises exception.
> 
> 
> 
> I have never used curses but I have used text screens. I suspect that 
> 
> addch moves the cursor to the position beyond where the character is 
> 
> added, but there is no such position. I remember having problems writing 
> 
> to the last char of a 24x80 screen without getting either a scroll or 
> 
> beep if scrolling was disabled.
> 
> 
> 
> > This is my problem. Why? How to fix it?
> 
> 
> 
> Perhaps this will help:
> 
> window.leaveok(yes)
> 
> If yes is 1, cursor is left where it is on update, instead of being at 
> 
> “cursor position.” This reduces cursor movement where possible. If 
> 
> possible the cursor will be made invisible.
> 
> 
> 
> > (If i will ignore exception, then last char will be displayed)
> 
> 
> 
> Otherwise, just catch the exception, as you already discovered.
> 
> 
> 
> > Here simple example: http://pastebin.com/SjyMsHZB
> 
> 
> 
> -- 
> 
> Terry Jan Reedy

Thank you.

I tried everything in my test script.
win.leaveok() - no effect
curses.cur_vis() - no effect
win.scrollok() - start newline and place cursor on it

It's only one last option:
on last line last char try/except with pass.

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#38711

[Multipart message — attachments visible in raw view] — view raw

Sent from my android phone.
On Feb 10, 2013 2:09 PM, "Vlasov Vitaly" <vnigtha@gmail.com> wrote:
>
> суббота, 9 февраля 2013 г., 23:22:47 UTC+4 пользователь Terry Reedy
написал:
> > On 2/9/2013 6:23 AM, Vlasov Vitaly wrote:
>
> > --
> >
> > Terry Jan Reedy
>
> Thank you.
>
> I tried everything in my test script.
> win.leaveok() - no effect
> curses.cur_vis() - no effect
> win.scrollok() - start newline and place cursor on it
>
> It's only one last option:
> on last line last char try/except with pass.

I doubt this is a Python 2 or Python 3 problem; historically some terminal
types curses supports could not fill the lower right-most character cell
without causing an undesired scroll of the screen by one line.  So portable
curses programs avoid filling that spot with anything.

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#38608

суббота, 9 февраля 2013 г., 23:22:47 UTC+4 пользователь Terry Reedy написал:
> On 2/9/2013 6:23 AM, Vlasov Vitaly wrote:
> 
> > Hello.
> 
> >
> 
> > I found strange behavior of curses module, that i can't understand. I
> 
> > initialize screen with curses.initscr(), then i create subwin of
> 
> > screen with screen.subwin(my_subwin_sizes). After that i fill subwin
> 
> > with my_char in for-loop. On last char in last line subwin.addch()
> 
> > raises exception.
> 
> 
> 
> I have never used curses but I have used text screens. I suspect that 
> 
> addch moves the cursor to the position beyond where the character is 
> 
> added, but there is no such position. I remember having problems writing 
> 
> to the last char of a 24x80 screen without getting either a scroll or 
> 
> beep if scrolling was disabled.
> 
> 
> 
> > This is my problem. Why? How to fix it?
> 
> 
> 
> Perhaps this will help:
> 
> window.leaveok(yes)
> 
> If yes is 1, cursor is left where it is on update, instead of being at 
> 
> “cursor position.” This reduces cursor movement where possible. If 
> 
> possible the cursor will be made invisible.
> 
> 
> 
> > (If i will ignore exception, then last char will be displayed)
> 
> 
> 
> Otherwise, just catch the exception, as you already discovered.
> 
> 
> 
> > Here simple example: http://pastebin.com/SjyMsHZB
> 
> 
> 
> -- 
> 
> Terry Jan Reedy

Thank you.

I tried everything in my test script.
win.leaveok() - no effect
curses.cur_vis() - no effect
win.scrollok() - start newline and place cursor on it

It's only one last option:
on last line last char try/except with pass.

[toc] | [prev] | [standalone]

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