exp_consume.pony

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use json = "../json"

class val ExpConsume is NodeData
  """A consume expression."""

  let cap: (NodeWith[Keyword] | None)
  let body: NodeWith[Expression]

  new val create(
    cap': (NodeWith[Keyword] | None),
    body': NodeWith[Expression])
  =>
    cap = cap'
    body = body'

  fun name(): String => "ExpConsume"

  fun val clone(updates: ChildUpdateMap): NodeData =>
    ExpConsume(
      _map_or_none[Keyword](cap, updates),
      _map_with[Expression](body, updates))

  fun add_json_props(node: Node box, props: Array[(String, json.Item)]) =>
    match cap
    | let cap': NodeWith[Keyword] =>
      props.push(("cap", node.child_ref(cap')))
    end
    props.push(("body", node.child_ref(body)))

primitive ParseExpConsume
  fun apply(obj: json.Object val, children: NodeSeq): (ExpConsume | String) =>
    let cap =
      match ParseNode._get_child_with[Keyword](
        obj,
        children,
        "cap",
        "ExpConsume.cap must be a Keyword",
        false)
      | let node: NodeWith[Keyword] =>
        node
      | let err: String =>
        return err
      end
    let body =
      match ParseNode._get_child_with[Expression](
        obj,
        children,
        "body",
        "ExpConsume.body must be an Expression")
      | let node: NodeWith[Expression] =>
        node
      | let err: String =>
        return err
      else
        return "ExpConsume.body must be an Expression"
      end
    ExpConsume(cap, body)