zsh prompts (showing git branch and rvm version with gemset)

# Prompts
autoload colors ; colors

git_prompt_info() {
  ref=$(git symbolic-ref HEAD 2> /dev/null) || return
  echo ${ref#refs/heads/}
}

rvm_version() {
  gemset=$(echo $GEM_HOME | awk -F'@' '{print $2}')
  version=$(echo $MY_RUBY_HOME | awk -F'-' '{print $2}')
  if [ "$gemset" != "" ] && [ "$version" != "" ]; then
    echo "$version%%$gemset"
  fi
}

prompt_info() {
  git=$(git_prompt_info)
  if [ "$git" != "" ]; then
    rvm=$(rvm_version)
    if [ "$rvm" != "" ]; then
      echo " [$git $rvm]"
    else
      echo " [$git]"
    fi
  fi
}

PROMPT='%n@%m%{$fg[green]%}$(prompt_info)%{$fg_bold[blue]%} ~ %{$reset_color%}'
RPROMPT=' %~'                 # prompt for right side of screen