Notation - The Rust Reference

# Notation

## Grammar

The following notations are used by the Lexer and Syntax grammar snippets:

Notation | Examples | Meaning
--- | --- | ---
CAPITAL | KW_IF, INTEGER_LITERAL | A token produced by the lexer
ItalicCamelCase | LetStatement, Item | A syntactical production
`string` | `x`, `while`, `*` | The exact character(s)
\x | \n, \r, \t, \0 | The character represented by this escape
x? | `pub`? | An optional item
x* | OuterAttribute* | 0 or more of x
x+ | MacroMatch+ | 1 or more of x
xa..b | HEX_DIGIT1..6 | a to b repetitions of x
| | `u8` | `u16`, Block | Item | Either one or another
[ ] | [`b` `B`] | Any of the characters listed
[ - ] | [`a`-`z`] | Any of the characters in the range
~[ ] | ~[`b` `B`] | Any characters, except those listed
~`string` | ~`\n`, ~`*/` | Any characters, except this sequence
( ) | (`,` Parameter)? | Groups items

## String table productions

Some rules in the grammar — notably unary operators, binary operators, and keywords — are given in a simplified form: as a listing of printable 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 in `monospace` font occurs inside the grammar, it is an implicit reference to a single member of such a string table production. See tokens for more information.