Visual aid to determine the current keymap with Vi keybindings

[antoineco]

First of all, excellent job with the prompt 👏 I discovered today that Zim had a "new" default prompt after reinstalling my machine, and it is so simple and functional that I want to use it instead of Pure.

Is your feature request related to a problem? Please describe.

When Vi keybindings are enabled (bindkey -v) there is no visual aid to determine whether zle's current keymap is viins (insert mode, default) or vicmd (command mode, when pressing ESC).

I think making such visual aid part of the prompt would be sensible because:

1. Vi keybindings are built into Zsh
2. The keymap configuration is part of Zim's default configuration

Describe the solution you'd like

• Option 1 (preferred)

  Change the prompt symbol to another character of the ASCII table while the vicmd keymap is active. There aren't that many but, as an example, the extended ASCII table contains § (char 167), which should be available in any font and is quite subtle.

  It looks like below (viins / vicmd):

  
  

• Option 2

  Change the color of the prompt symbol to something other than green or red while the vicmd keymap is active. I suggest cyan because it is somewhat close to green, yet distinguishable.

  Potential issue: the red color coding — which indicates that the previous command failed — is lost while in vicmd mode, unless translated to yet another color like magenta. I'm not yet sure how I'd feel about that.

  It looks like below (viins / vicmd):

  
  

Describe alternatives you've considered

Spaceship includes a text indicator ([I] / [N]) on the first line, which I find bloated.

Starship allows configuring the shape and color of the prompt symbol in different states, which I find interesting and well designed. But considering the minimal nature of asciiship, I think a sane default that people can customize by forking the prompt's code would be enough.

Changing the terminal's cursor shape while changing mode e.g. from beam to block and back — like in Vim itself — would be controversial and error prone.

Additional context

-

[ericbn]

Hi @antoineco. So good to know you like our lightweight prompt theme! :- D

Not sure which indicator to pick for the vicmd keymap. We're already using # when root, % otherwise. I'd rather keep just the lower ASCII chars for this prompt. Also, it's already green or red depending on the exit status of the last command. I agree changing the terminal cursor shape is controversial and error prone.

If you want to experiment with it yourself, we have two themes that have vicmd keymap indicators implemented:

• sorin
• s1ck94

It's quite a good amount of additional code.

[ericbn]

This is what I've come up with: changing the prompt indicator to standout when in vicmd.

diff --git a/asciiship.zsh-theme b/asciiship.zsh-theme
index def650b..7641305 100644
--- a/asciiship.zsh-theme
+++ b/asciiship.zsh-theme
@@ -1,5 +1,23 @@
 # vim:et sts=2 sw=2 ft=zsh

+_prompt_asciiship_vimode() {
+  case ${KEYMAP} in
+    vicmd) print -n '%S%#%s' ;;
+    *) print -n '%#' ;;
+  esac
+}
+
+_prompt_asciiship_keymap_select() {
+  zle reset-prompt
+  zle -R
+}
+if autoload -Uz is-at-least && is-at-least 5.3; then
+  autoload -Uz add-zle-hook-widget && \
+      add-zle-hook-widget -Uz keymap-select _prompt_asciiship_keymap_select
+else
+  zle -N zle-keymap-select _prompt_asciiship_keymap_select
+fi
+
 typeset -g VIRTUAL_ENV_DISABLE_PROMPT=1

 setopt nopromptbang prompt{cr,percent,sp,subst}
@@ -31,5 +49,5 @@ fi

 PS1='
 %(2L.%B%F{yellow}(%L)%f%b .)%(!.%B%F{red}%n%f%b in .${SSH_TTY:+"%B%F{yellow}%n%f%b in "})${SSH_TTY:+"%B%F{green}%m%f%b in "}%B%F{cyan}%~%f%b${(e)git_info[prompt]}${VIRTUAL_ENV:+" via %B%F{yellow}${VIRTUAL_ENV:t}%b%f"}${duration_info}
-%B%(1j.%F{blue}*%f .)%(?.%F{green}.%F{red}%? )%#%f%b '
+%B%(1j.%F{blue}*%f .)%(?.%F{green}.%F{red}%? )$(_prompt_asciiship_vimode)%f%b '
 unset RPS1

[antoineco]

I hadn't though about standout, that could be a good approach I think! Underline comes to mind too.

I know that the screen-* / tmux-* terminfos that ship with macOS don't include italics and standout, but

• those are much less common than xterm-*
• a lot of macOS users who rely on these capabilities either enable them manually or recompile their terminfo from a more recent ncurses to enable them

I'll try your patch today and report here.
Thanks for looking into this so quickly!

[antoineco]

Contrary to what I remembered, standout does work perfectly fine in tmux on macOS, with the default tmux config (TERM=screen-256color) and the OS' default terminfo.
It also works in various terminal emulators I've tried on macOS, with various xterm terminfo variants.

tmux 3.3, screen-256color

Terminal.app, xterm-256color

Kitty, xterm-kitty

---

Patch applied, I think it looks great:

---

Underline wouldn't be very clear (and is probably not as widely supported as standout):