type RefCallbackFunc func(ref *spec.Ref) *spec.Ref

var RefCallbackNoop RefCallbackFunc = func(ref *spec.Ref) *spec.Ref {
	return ref
}

type SchemaCallbackFunc func(schema *spec.Schema) *spec.Schema

var SchemaCallBackNoop SchemaCallbackFunc = func(schema *spec.Schema) *spec.Schema {
	return schema
}

type Walker struct {
	// SchemaCallback will be called on each schema, taking the original schema,
	// and before any other callbacks of the Walker.
	// If the schema needs to be mutated, DO NOT mutate it in-place,
	// always create a copy, mutate, and return it.
	SchemaCallback func(schema *spec.Schema) *spec.Schema

	// RefCallback will be called on each ref.
	// If the ref needs to be mutated, DO NOT mutate it in-place,
	// always create a copy, mutate, and return it.
	RefCallback func(ref *spec.Ref) *spec.Ref
}