In Rust, this can almost be expressed as `arg: &'static str` to accept a reference to a string whose lifetime never ends. I say “almost” because this allows both string literals and references to static (but dynamically generated) string.

For Rust’s macros, a literal can be expressed as `$arg:lit`. This does allow other literals as well, such as int or float literals, but typically the generated code would only work for a string literal.