I'm using vi mode as my editor mode in zsh (bindkey -v).

Normal pormpts (part of oh-my-zshell or prezto) are implemented in zsh and they are taking advantage of zle-keymap-select and changing part of the prompt based on $KEYMAP variable.

This is very simple example:

function zle-line-init zle-keymap-select {
    RPS1="${${KEYMAP/vicmd/-- NORMAL --}/(main|viins)/-- INSERT --}"
    RPS2=$RPS1
    zle reset-prompt
}

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

I'd like to know which vi mode (insert or command) am I using. Any idea how I could implement this feature in powerline-go? I could probably use the function zle-keymap-select to change the RPS1 command or set some environment variable and then call zle reset-prompt. What do you think?