Notation

CAPITAL_CASE

IDENTIFIER

A named nonterminal or lexer token

"string"

"if", "+"

The exact character(s)

`string`

`"`

Alternative syntax for exact character(s)

snake_case

let_stmt, item

A syntactical production

\x

\n, \r, \t, \0

The character represented by this escape

x?

pub?

An optional item

x*

item*

0 or more of x

x+

item+

1 or more of x

x{a}

[0-9a-fA-F]{2}

Exactly a repetitions of x

x\{a,b}

[0-9a-fA-F]\{1,6}

a to b repetitions of x

|

felt | int

Either one or another

[ ]

[bB]

Any of the characters listed

[ - ]

[a-z]

Any of the characters in the range

~[ ]

~[bB]

Any characters, except those listed

~"string"

~"\n", ~"*/"

Any characters, except this sequence

~CAPITAL_CASE

~EOL*

Any characters, except sequences matching the lexer token

( )

( "," parameter )?

Group items

/* text */

ITEM /* except IMPL_ITEM */

Human words supplementation