divert(`-1')
# foreach(x, (item_1, item_2, ..., item_n), stmt)
#   parenthesized list, simple version
define(`foreach', `pushdef(`$1')_foreach($@)popdef(`$1')')
define(`_arg1', `$1')
define(`_foreach', `ifelse(`$2', `()', `',
  `define(`$1', _arg1$2)$3`'$0(`$1', (shift$2), `$3')')')
divert`'dnl