[−][src]Function syntax::ext::tt::macro_parser::may_begin_with
fn may_begin_with(name: &str, token: &Token) -> bool
🔬 This is a nightly-only experimental API. (rustc_private
)
this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml
instead?
Checks whether a non-terminal may begin with a particular token.
Returning false
is a stability guarantee that such a matcher will never begin with that
token. Be conservative (return true) if not sure.