zsh - prompt redraw after executing command

Question

I just started using zsh and I'm configuring a few things. I've chosen the vi bindings as I'm more familiar with those. As many people before me, I soon found it would be useful to have some visual clue of the vi mode I'm in before I start typing.

Looking around various places I found a few that insert some text or other in the prompt. I've tried to adapt one of them to use a different color for my prompt, instead of adding text. Here is the relevant code:

setopt PROMPT_SUBST

VIMODE="$fg[red]"
function zle-line-init zle-keymap-select {
    VIMODE="${${KEYMAP/vicmd/$fg[green]}/(main|viins)/$fg[red]}"
    zle reset-prompt
}

zle -N zle-line-init zle-keymap-select

PROMPT='%{${VIMODE}%}%#%{$reset_color%} '

This would get a color directive inside the ${VIMODE} variable, red if it's on insert, green if it's on cmd. It works, and updates the color correctly, so far, for all the mode changes I've used (capital C or A, i, a).

But after running a command, the prompt becomes white until I start typing something (then it becomes red). Clearing the screen through ^L makes it redraw correctly.

Can anyone please check it and tell me where I'm doing things wrong? I'm pretty sure there's also a better way of conditionally changing the color than passing it through a variable.

Thanks in advance!

Edit:

Well, something really weird is happening and I don't understand it. I had to reboot my computer and when I opened a terminal the prompt stopped swapping colors between mode changes.

I took out the zle-line-init widget and source'd the .zshrc and, magically, not only does it work again, the original problem (white prompt after a command) is also gone.

So this is the current state of affairs, and I'm not sure if this'll happen again or not.

VIMODE="$fg[red]"

function zle-keymap-select {
    VIMODE="${${KEYMAP/vicmd/$fg[green]}/(main|viins)/$fg[red]}"
    zle reset-prompt
}

zle -N zle-keymap-select

Does anybody know what could've been the factors involved in this?

I originally did not restart the terminal, just sourced the .zshrc to load everything up. Could something have side effects because of this?

Thanks.

Answer 1

zle -N zle-line-init zle-keymap-select creates a widget called zle-line-init that's implemented by the function zle-keymap-select.

So, originally, your function zle-keymap-select was executed every time the line editor was started to read a new line of input, but your function was never called when you changed keymaps.

Also, doing source ~/.zshrc is a BAD IDEA that can lead to all kinds of weird problems. Instead, just restart your terminal or do exec zsh for changes in your .zshrc file to take effect.