rust-lang/regex

In regex's no-std impl of Lazy it's possible for 2 threads to race and both run the init func at the same time. Contrast that to std::sync::LazyLock which guarantees the unit function only runs once…

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I'd like to add a simple macro to `regex` for building a regex once and then using it via `LazyLock` (or similar). But I'm having trouble with the name. Should it be `regex::regex!(..)` or…