Function walk

packages/core/src/effect/layer-node.ts:171–209

(
  root: AnyNode,
  visit: Visit<Result>,
  options: {
    readonly cache?: Map<AnyNode, Result>
    readonly resolve?: (node: AnyNode) => AnyNode
    readonly detectCycles?: boolean
  } = {},
)

}

function walk<Result>(
  root: AnyNode,
  visit: Visit<Result>,
  options: {
    readonly cache?: Map<AnyNode, Result>
    readonly resolve?: (node: AnyNode) => AnyNode
    readonly detectCycles?: boolean
  } = {},
) {
  const cache = options.cache ?? new Map<AnyNode, Result>()
  const visiting = new Set<AnyNode>()
  const stack: AnyNode[] = []

  const recur = (node: AnyNode): Result => {
    const target = options.resolve?.(node) ?? node
    const cached = cache.get(target)
    if (cached !== undefined || cache.has(target)) return cached!

    if (options.detectCycles !== false && visiting.has(target)) {
      const start = stack.indexOf(target)
      throw new Error(
        `Cycle detected in layer tree: ${[...stack.slice(start), target].map((item) => item.name).join(" -> ")}`,
      )
    }

    visiting.add(target)
    stack.push(target)
    try {
      const result = visit(target, { cache, visit: recur })
      if (!cache.has(target)) cache.set(target, result)
      return result
    } finally {
      stack.pop()
      visiting.delete(target)
    }
  }

  return recur(root)
}

export function hoist<A, E, T extends Tag, const Items extends Replacements = readonly []>(
  root: Node<A, E, any>,