Reimplement ZSH transient prompt

.zshrc

@@ -32,4 +32,57 @@ bindkey '^x^e' edit-command-line
 # Load any kind of system-local stuff
 [[ ! -f ~/.zshrc.local ]] || source ~/.zshrc.local
 
+# Transient prompt
+_prompt () {
+    local retval=$?
+
+    # Echo compact prompt
+    if (( $_vbe_prompt_compact )); then
+        echo '\e[32m\e[0m '
+        return
+    fi
+
+    # Echo main prompt
+    starship prompt
+}
+setopt prompt_subst
+
+_zle-line-init() {
+    [[ $CONTEXT == start ]] || return 0
+
+    # Start regular line editor
+    (( $+zle_bracketed_paste )) && print -r -n - $zle_bracketed_paste[1]
+    zle .recursive-edit
+    local -i ret=$?
+    (( $+zle_bracketed_paste )) && print -r -n - $zle_bracketed_paste[2]
+
+    # If we received EOT, we exit the shell
+    if [[ $ret == 0 && $KEYS == $'\4' ]]; then
+        _vbe_prompt_compact=1
+        zle .reset-prompt
+        exit
+    fi
+
+    # Line edition is over. Shorten the current prompt.
+    _vbe_prompt_compact=1
+    zle .reset-prompt
+    unset _vbe_prompt_compact
+
+    if (( ret )); then
+        # Ctrl-C
+        zle .send-break
+    else
+        # Enter
+        zle .accept-line
+    fi
+    return ret
+}
+
+zle -N zle-line-init _zle-line-init
+
+# Init starship
 eval "$(starship init zsh)"
+
+# Pull back to our transient prompt
+# We call starship within the prompt function when warranted
+PS1='$(_prompt)'