rust - 除了关键字之外，Rust 是否有任何保留的标识符(例如以下划线开头)？

Question

在 C++ 中，certain identifiers starting with underscores are reserved to be used by the compiler or the standard library . Rust 中的标识符有类似的规则吗？当然，不允许使用关键字(如 if)作为标识符，但除此之外:我可以使用任何我想要的标识符吗？

Answer 1

根据Rust Reference , 标识符可以以下划线开头，除了长度(不仅仅是下划线)和关键字之外似乎没有其他限制:

An identifier is any nonempty Unicode (see note) string of the following form:

Either

• The first character has property XID_start
• The remaining characters have property XID_continue

Or

• The first character is _
• The identifier is more than one character, _ alone is not an identifier
• The remaining characters have property XID_continue

that does not occur in the set of keywords.

note: Non-ASCII characters in identifiers are currently feature gated.

XID_start 和 XID_continue 是 properties Unicode code points ;例如(最值得注意的是)数字没有 XID_start 属性，因此不能作为标识符的第一个字符。