visual line movement

visual line movement

[Anthony Heading]

Is there a good way to make zle up-/down-line etc operate visually, i.e. have the cursor position move across wrapped lines on the screen rather than considering only embedded '\n's in the buffer?   I'm guessing not, but would like to be sure.

Re: visual line movement

[Peter Stephenson]

On Fri, 27 Jul 2018 03:10:37 -0400
Anthony Heading <anthony@ajrh.net> wrote:
> Is there a good way to make zle up-/down-line etc operate visually,
> i.e. have the cursor position move across wrapped lines on the screen
> rather than considering only embedded '\n's in the buffer?   I'm
> guessing not, but would like to be sure.

Unless I'm missing something, it's not possible without adding a
separate calculation of where the lines on screen will go.  The
function that redraws the screen keeps its information separately from
the body of ZLE and, although it does remember what it's put where,
there's no mapping between the screen lines and the logical data to
refer to.

pws

Re: visual line movement

[Daniel Shahaf]

Peter Stephenson wrote on Fri, 27 Jul 2018 09:30 +0100:
> On Fri, 27 Jul 2018 03:10:37 -0400
> Anthony Heading <anthony@ajrh.net> wrote:
> > Is there a good way to make zle up-/down-line etc operate visually,
> > i.e. have the cursor position move across wrapped lines on the screen
> > rather than considering only embedded '\n's in the buffer?   I'm
> > guessing not, but would like to be sure.
> 
> Unless I'm missing something, it's not possible without adding a
> separate calculation of where the lines on screen will go.  The
> function that redraws the screen keeps its information separately from
> the body of ZLE and, although it does remember what it's put where,
> there's no mapping between the screen lines and the logical data to
> refer to.

A workaround is to use edit-command-line:

http://zsh.sourceforge.net/FAQ/zshfaq03.html#l45

Re: visual line movement

[Mikael Magnusson]

On Fri, Jul 27, 2018 at 9:10 AM, Anthony Heading <anthony@ajrh.net> wrote:
> Is there a good way to make zle up-/down-line etc operate visually, i.e. have the cursor position move across wrapped lines on the screen rather than considering only embedded '\n's in the buffer?   I'm guessing not, but would like to be sure.

If you make a custom widget that moves $COLUMNS characters left/right,
the effect should be approximately the same.

-- 
Mikael Magnusson

Re: visual line movement

[Anthony Heading]

On Fri, Jul 27, 2018, at 5:53 AM, Mikael Magnusson wrote:
> If you make a custom widget that moves $COLUMNS characters left/right, the effect
> should be approximately the same.

Agreed, though that loses the '\n' handling that the base widget does perfectly, and
it would be nice to think about Unicode, and maybe there are additional sources of
infelicities too.

For my education, I'll try to find the drawing code that Peter mentions and see what
it aims to handle.  The COMBINING_CHARS option looks instructive.

It being 2018 and all, I wonder if reading the cursor position from the terminal
after each character is a workable option.

Re: visual line movement

[Peter Stephenson]

On Fri, 27 Jul 2018 07:50:31 -0400
Anthony Heading <anthony@ajrh.net> wrote:
> It being 2018 and all, I wonder if reading the cursor position from
> the terminal after each character is a workable option.

Experience suggests terminals all have a wide array of different
limitations --- so I wouldn't be surprised if you can find one
terminal where this works.

pws