oh-my-zsh avit theme: instead of only showing the last 3 directories in the...

oh-my-zsh avit theme: instead of only showing the last 3 directories in the $PWD shorten the path by removing some middle parts if $PWD becomes too long.

themes/avit.zsh-theme

 # AVIT ZSH Theme
 
 PROMPT='
-$(_user_host)${_current_dir} $(git_prompt_info) $(_ruby_version)
+$(_user_host)$(_current_dir) $(git_prompt_info) $(_ruby_version)
 %{$fg[$CARETCOLOR]%}▶%{$resetcolor%} '
 
 PROMPT2='%{$fg[grey]%}◀%{$reset_color%} '
 
 RPROMPT='$(_vi_status)%{$(echotc UP 1)%}$(_git_time_since_commit) $(git_prompt_status) ${_return_status}%{$(echotc DO 1)%}'
 
-local _current_dir="%{$fg_bold[blue]%}%3~%{$reset_color%} "
 local _return_status="%{$fg_bold[red]%}%(?..⍉)%{$reset_color%}"
 local _hist_no="%{$fg[grey]%}%h%{$reset_color%}"
 
+function _current_dir() {
+  local _max_pwd_length="65"
+  if [[ $(echo -n $PWD | wc -c) -gt ${_max_pwd_length} ]]; then
+    echo "%{$fg_bold[blue]%}%-2~ ... %3~%{$reset_color%} "
+  else
+    echo "%{$fg_bold[blue]%}%~%{$reset_color%} "
+  fi
+}
+
 function _user_host() {
   if [[ -n $SSH_CONNECTION ]]; then
     me="%n@%m"