ruby - 合并运算符是官方 YAML 吗？

Question

我见过一些 YAML 文件使用“合并”运算符 << .这是来自 yaml.org 上“Yaml Cookbook”的示例:

mapping:
  name: Joe
  job: Accountant
  <<:
    age: 38

另一方面，我在 yaml.org 的规范文档中找不到任何对合并运算符的引用。

这个运算符是 YAML 的正式部分，还是只是 Ruby 实现的一部分？

Answer 1

http://yaml.org/type/merge.html

Specify one or more mappings to be merged with the current one.

The “<<” merge key is used to indicate that all the keys of one or more specified maps should be inserted into the current map. If the value associated with the key is a single mapping node, each of its key/value pairs is inserted into the current mapping, unless the key already exists in it. If the value associated with the merge key is a sequence, then this sequence is expected to contain mapping nodes and each of these nodes is merged in turn according to its order in the sequence. Keys in mapping nodes earlier in the sequence override keys specified in later mapping nodes.

更多信息在 http://yaml.org/type/