zsh/Completion/Builtins/_popd

#compdef popd

# This just completes the numbers after +, showing the full directory list
# with numbers. For - we do the same thing, but reverse the numbering (other
# way round if pushdminus is set). Note that this function is also called
# from _cd for cd and pushd.

setopt extendedglob nonomatch

local expl list lines revlines disp

! zstyle -T ":completion:${curcontext}:directory-stack" prefix-needed ||
    [[ $PREFIX = [-+]* ]] || return 1

_wanted directory-stack || return 1

if zstyle -T ":completion:${curcontext}:directory-stack" verbose; then
  # get the list of directories with their canonical number
  # and turn the lines into an array, removing the current directory
  lines=("${dirstack[@]}")

  if [[ ( $PREFIX[1] = - && ! -o pushdminus ) ||
        ( $PREFIX[1] = + && -o pushdminus ) ]]; then
    integer i
    revlines=( $lines )
    for (( i = 1; i <= $#lines; i++ )); do
      lines[$i]="$((i-1)) -- ${revlines[-$i]##[0-9]#[	 ]#}"
    done
  else
    for (( i = 1; i <= $#lines; i++ )); do
      lines[$i]="$i -- ${lines[$i]##[0-9]#[	 ]#}"
    done
  fi
  # get the array of numbers only
  list=( ${PREFIX[1]}${^lines%% *} )
  disp=( -ld lines )
else
  list=( ${PREFIX[1]}{0..${#dirstack}} )
  disp=()
fi

_loop -V directory-stack expl 'directory stack' \
    compadd "$@" "$disp[@]" -Q - "$list[@]"