Refactor-Recursive-Tree-Visitor

The model receives the prompt (and optional system message). The run uses scorer rubric_json_metrics with the JSON configuration below. Pass/fail and partial credit are determined entirely by that scorer against the model output; no human grading.

Return JSON only with keys refactor, rationale, tests. Refactor a recursive tree visitor into an explicit stack to avoid call stack overflow. Preserve traversal order.

{
  "metrics": {
    "visible": {
      "checks": [
        {
          "contains": [
            "explicit stack"
          ]
        },
        {
          "contains": [
            "recursive"
          ]
        },
        {
          "contains": [
            "tree visitor"
          ]
        }
      ]
    },
    "hidden": {
      "checks": [
        {
          "contains": [
            "traversal order"
          ]
        },
        {
          "contains": [
            "call stack"
          ]
        },
        {
          "contains": [
            "overflow"
          ]
        }
      ]
    },
    "intent": {
      "checks": [
        {
          "contains": [
            "control flow"
          ]
        },
        {
          "contains": [
            "iteration"
          ]
        },
        {
          "contains": [
            "refactor"
          ]
        }
      ]
    }
  }
}