Zsh shell function 'ec' for opening emacsclient in an sshd or mosh session

ec.sh

#! /bin/zsh

function pid_has_ancestor_server() {
  pstree -p $1 | grep $2
}

function pid_of_shell_process() {
  if is_not_inside_local_tmux; then
    echo "$$"    
  else
    # current shell is under tmux
    local tmux_current_session=$(tmux display-message -p '#S')
    local tmux_client_id=$(tmux list-clients -t "${tmux_current_session}" -F '#{client_pid}')
    # echo $tmux_current_session $tmux_client_id
    echo "$tmux_client_id"
  fi
}

function is_shell_parented_by_server() {
  local pid=$(pid_of_shell_process)
  local parent_found=$(pid_has_ancestor_server $pid $1)   # or empty if not found
  if [[ -z "$parent_found" ]]; then
    return 1;    # exit code 1: no such parent process
  fi

  return 0;      # exit code 0: parent process found
}

function is_shell_parented_by_server() {
  local pid=$(pid_of_shell_process)
  local parent_found=$(pid_has_ancestor_server $pid $1)   # or empty if not found
  if [[ -z "$parent_found" ]]; then
    return 1;    # exit code 1: no such parent process
  fi

  return 0;      # exit code 0: parent process found
}

function is_mosh() {
  # Prevent grep from showing up in ps results
  # by forcing regex match by putting [] around first character
  # https://unix.stackexchange.com/questions/74185/how-can-i-prevent-grep-from-showing-up-in-ps-results
  return $(is_shell_parented_by_server "[m]osh-server");
}

function is_sshd() {
  return $(is_shell_parented_by_server "[s]shd");
}

function ec()
{
  # In console mode, just open a tty into emacs
  # aargh: what about when we're SSHing into Bali when
  # it actually has a Emacs graphical frame running but
  # we're in console mode?

  if { is_sshd || is_mosh } then     
    emacsclient -t "$@"
  else
    # Open a new graphical frame if one does not exist, otherwise reuse the existing one
    # From http://superuser.com/questions/358037/emacsclient-create-a-frame-if-a-frame-does-not-exist/862809#862809
    found=`emacsclient -n -e "(if (> (length (frame-list)) 1) 't)" | grep t`
    if [ "$found" = "t" ]; then
      emacsclient -n -a "" "$@"
    else
      emacsclient -c -n -a "" "$@"
    fi
  fi
}