Vie-Validator中rule表示什么意思？

http://vuejs.github.io/vue-validator/zh-cn/errors.html

<validator name="validation1">
  <div class="username">
    <label for="username">username:</label>
    <input id="username" type="text" v-validate:username="{
      required: { rule: true, message: 'required you name !!' }
    }">
    <span v-if="$validation1.username.required">{{ $validation1.username.required }}</span>
  </div>
  <div class="password">
    <label for="password">password:</label>
    <input id="password" type="password" v-validate:password="{
      required: { rule: true, message: 'required you password !!' },
      minlength: { rule: 8, message: 'your password short too !!' }
    }"/>
    <span v-if="$validation1.password.required">{{ $validation1.password.required }}</span>
    <span v-if="$validation1.password.minlength">{{ $validation1.password.minlength }}</span>
  </div>
</validator>

上面代码中的

    <input id="password" type="password" v-validate:password="{
      required: { rule: true, message: 'required you password !!' },
      minlength: { rule: 8, message: 'your password short too !!' }
    }"/>

具体如何理解？

---

rule 这里可以翻译为 规则