[BUG] Line number in prompt after `zle reset-prompt'

[BUG] Line number in prompt after `zle reset-prompt'

[Sebastian Gniazdowski]

Hello
To reproduce:

PROMPT="%i # "
a() { zle reset-prompt }
zle -N a
bindkey "^E" a

and press Ctrl-E. Line number will change, most probably to "0", but
in my other large script it changes to 50 and other numbers, depending
on what I do with the script

Best regards,
Sebastian Gniazdowski

Re: [BUG] Line number in prompt after `zle reset-prompt'

[Bart Schaefer]

On Oct 31,  7:42pm, Sebastian Gniazdowski wrote:
}
} PROMPT="%i # "
} a() { zle reset-prompt }
} zle -N a
} bindkey "^E" a
} 
} and press Ctrl-E. Line number will change

Not sure this is a bug:

%N
     The name of the script, sourced file, or shell function that zsh is
     currently executing, whichever was started most recently.

%i
     The line number currently being executed in the script, sourced
     file, or shell function given by %N.

If you use:

    PROMPT="%N %i # "

and then press ^E, you will see

    a 0 # 

which is correct, the line number in the function "a" is 0.

Re: [BUG] Line number in prompt after `zle reset-prompt'

[Sebastian Gniazdowski]

I would say it's not a bug. I found it possible to replace
"reset-prompt" with "redisplay" which doesn't re-expand prompt.
However, there is one interesting thing:

PROMPT=" %i # "
a() { zle redisplay }
zle -N a
b() { zle redisplay; zle -M "test" }
zle -N b
c() { zle -M "test" }
zle -N c
bindkey "^E" a
bindkey "^R" b
bindkey "^T" c

"a" and "c" will not reexpand prompt, while "b" will, apparently with no reason

Best regards,
Sebastian Gniazdowski


On 31 October 2015 at 21:23, Bart Schaefer <schaefer@brasslantern.com> wrote:
> On Oct 31,  7:42pm, Sebastian Gniazdowski wrote:
> }
> } PROMPT="%i # "
> } a() { zle reset-prompt }
> } zle -N a
> } bindkey "^E" a
> }
> } and press Ctrl-E. Line number will change
>
> Not sure this is a bug:
>
> %N
>      The name of the script, sourced file, or shell function that zsh is
>      currently executing, whichever was started most recently.
>
> %i
>      The line number currently being executed in the script, sourced
>      file, or shell function given by %N.
>
> If you use:
>
>     PROMPT="%N %i # "
>
> and then press ^E, you will see
>
>     a 0 #
>
> which is correct, the line number in the function "a" is 0.

Re: [BUG] Line number in prompt after `zle reset-prompt'

[Bart Schaefer]

On Nov 1,  4:18pm, Sebastian Gniazdowski wrote:
}
} a() { zle redisplay }
} b() { zle redisplay; zle -M "test" }
} c() { zle -M "test" }
} 
} "a" and "c" will not reexpand prompt, while "b" will, apparently with
} no reason

Each of redisplay and -M is setting a different flag indicating that
a part of the prompt, buffer, and "status line" needs to be redrawn.
Only when both of the of those flags are set is the display considered
to be in a sufficiently indeterminate state that the whole thing needs
to be regenerated.

(If you reverse "zle -M" + "zle redisplay" the prompt will start to
climb up the screen and the -M text will never appear, because those
two flags are now being considered in the wrong order.)

Ultimately this is because ZLE does not attempt to do "full screen"
management of the display, i.e., it does not maintain a full internal
mapping of the display to minimize updates; it only tracks horizontal
positions where the prompt starts and ends, and number of lines used
by the prompt and the buffer.  So it will do a complete repaint in
some circumstances that might seem unnecessary.