swf-runtime 1.0.0-alpha9

document:
  dsl: '1.0.0'
  namespace: test
  name: for-custom-at
  version: '0.1.0'
do:
  - processItems:
      for:
        in: ${ .items }
        at: idx
        each: item
      do:
        - logItem:
            set:
              result: "${ [.result[]] + [{idx: $idx, item: $item}] }"