A few productions in Rust's grammar permit Unicode code points outside the ASCII range. We define these productions in terms of character properties specified in the Unicode standard, rather than in terms of ASCII-range code points. The grammar has a Special Unicode Productions section that lists these productions.

Some rules in the grammar — notably unary operators, binary operators, and keywords — are given in a simplified form: as a listing of a table of unquoted, printable whitespace-separated strings. These cases form a subset of the rules regarding the token rule, and are assumed to be the result of a lexical-analysis phase feeding the parser, driven by a DFA, operating over the disjunction of all such string table entries.

When such a string enclosed in double-quotes (") occurs inside the grammar, it is an implicit reference to a single member of such a string table production. See tokens for more information.