gistfile1.eclass

function git_rev_head
{
  # Can declare multiple variables on one line IFS separated.
  # By default IFS is "white characters"
  local rev_prompt_token=" » " rev=1 sym=0 sym_prompt="" rev_prompt="" \
        colors=() branches=()

  # If git branches contain whitespace, then the following should be quoted.
  branches[$rev]="$(git name-rev --name-only head 2> /dev/null)"
  branches[$sym]="$(git symbolic-ref -q head 2> /dev/null)"
  branches[$sym]="${branches[$sym]##refs/heads/}"

  # Use [[ not [ as [[ is builtin and [ is an external process,
  #  specifically/bin/test
  if [[ ${#branches} -gt 0 ]]; then
    for branch in $sym $rev; do
      case "${branches[$branch]}" in
        production*|master*) 
          colors[$branch]="${bold}${red_text}"
          ;;
        merge_*) 
          colors[$branch]="${cyan_text}"
          ;;
        feature_*) 
          colors[$branch]="${yellow_text}"
          ;;
        *) 
          colors[$branch]="${green_text}"
          ;;
      esac
    done

    sym_prompt="${colors[$sym]}${branches[$sym]}${reset}"
    rev_prompt="${colors[$rev]}${branches[$rev]}${reset}${rev_prompt_token}"

    if [[ "${branches[$sym]}" = "${branches[$rev]}" ]]; then
      rev_prompt=""
    fi

    echo "(${rev_prompt}${sym_prompt})"
  fi
}