zsh/Completion/User/_user_at_host

#autoload

# Complete user/host combinations. Normally this looks for the style
# `users-hosts' for the tag `accounts'. A different tag may be given
# with `-t tag'.
# A `-' or `--' as the first argument is ignored.

local suf tag=accounts

if [[ "$1" = -t?* ]]; then
  tag="${1[3,-1]}"
  shift
elif [[ "$1" = -t ]]; then
  tag="$2"
  shift 2
fi

[[ "$1" = -(|-) ]] && shift

if [[ -prefix 1 *@ ]]; then
  local user=${PREFIX%%@*}

  compset -P 1 '*@'

  _wanted -C user-at hosts expl "host for $user" \
      _combination -s '[:@]' "${tag}" users-hosts users="$user" hosts "$@" -
else
  compset -S '@*' || suf="@"
  _wanted users expl "user" \
      _combination -s '[:@]' "${tag}" users-hosts users -S "$suf" -q "$@" -
fi