-- type.yaml --
openapi: 3.0.0
info:
  title: Users schema
  version: v1beta1
  contact:
    name: The CUE Authors
    url: https://cuelang.org

components:
  schemas:
    User:
      description: "A User uses something."
      type: object
      properties:
        id:
          type: integer
        name:
          type: string
        address:
          $ref: "#/components/schemas/PhoneNumber"
    PhoneNumber:
      description: "The number to dial."
      type: string

-- out.cue --
// Users schema
package foo

info: {
	title:   "Users schema"
	version: "v1beta1"
	contact: {
		name: "The CUE Authors"
		url:  "https://cuelang.org"
	}
}
// A User uses something.
User :: {
	name?:    string
	id?:      int
	address?: PhoneNumber
	...
}

// The number to dial.
PhoneNumber :: string