Child-count Constraints

Constraining nested children with maxchildren and requiredchildren on @block.

§ 1Child-count constraints on @block

@block accepts two named arguments that constrain nested children: max_children = N caps the total nested-block count, and required_children = ["kind", ...] demands at least one child of each listed kind. Both are enforced by wcl check.

wcl

@block("stage", max_children = 4, required_children = ["step"])
type Stage {
  @inline(0) name: utf8
  @children("step") steps: list<Step>
}