Re: cursor position in a variable

[Mikael Magnusson <mikachu@xxxxxxxxx>]

On Sat, Sep 5, 2015 at 8:36 PM, david sowerby <d_sowerby@xxxxxxxxx> wrote:
> I can get the cursor position by doing:
> print "\e[6n"
> this gives me the row and column. Though oddly the output appears after the next prompt, not on its own line. This
> may (or nor) be why when I do:
> pos=$(print "\e[6n")
> print $pos
> I get an empty line - and the output after the next prompt.
> I want to use the row the cursor is on in a script -- so how do I get that into a variable? If not this way is there a way using ZLE?
> thanks for any help   --------------dave

When you print a terminal control sequence, the terminal writes the
reply on standard input, so you need something like

print -n '\e[6n'
read pos

The problem here is that the terminal doesn't print a newline, so this
will hang until you press enter. You can dance around with a loop
reading one character at a time and checking if there is more pending
input, but I'm not 100% sure what the best way to handle this is. If
'read' had an option "read all pending input", it would be easy, but
it does not. :)

print -n '\e[6n'
pos=
while IFS= read -rs -t 0.1 -k1; do pos+=$REPLY; done
echo ${(V)pos}

this "works", but the 0.1 feels hacky. With 0, the whole loop might
abort before the terminal has time to write any characters back.

print -n '\e[6n'
until IFS= read -rs -k1 pos; do done
while IFS= read -rs -t 0 -k1; do pos+=$REPLY; done
echo ${(V)pos}

this variant will spin until it gets one character back, then read the
rest of the pending characters. You may also want to abort that loop
when you get the "R" back.
...; do pos+=$REPLY; [[ $REPLY == R ]] && break; done

-- 
Mikael Magnusson