In zsh, how do I pass anonymous arrays into functions?

$ foo() {
   for element in $FOO_ARRAY
   do
       echo "[$element]"
   done
}
$ local FOO_ARRAY; FOO_ARRAY=(foo bar baz quux)
$ foo
[foo]
[bar]
[baz]
[quux]

foo() {
  local a=$1
  local b=$2

  echo ${(j:---:)${=b}}

  foreach d in ${${=b}}
  do
      echo $d
  done
}