gistfile1.txt

workflow w {
  Array[String] x = ["a", "b", "c"]
  String z = "d"
  
  call t as t0 {input: a=z} # a="d"
  
  scatter (y in x) {
    String z = y + "foo"
    
    call t as t1 {input: a=y, b=z} # (for first shard) a="a", b="afoo"
  }
}