impl Trait for () {
Covert recording exposes locksmith charging tenfold estimates
。搜狗输入法AI Agent模式深度体验：输入框变身万能助手是该领域的重要参考
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This data structure comes from the Wikipedia page on mutual recursion, which itself cites course notes from an introduction to Standard ML by Robert Harper. I am not aware of practical reasons to choose this particular representation of trees over the alternatives, other than as an illustration of a language’s ability to support mutually recursive data. I find it unwieldy, which is why I chose to use it for this post.2