string: '`' {.} '`' | '"' {.} '"';

_bin_digit: '0' - '1';
_oct_digit: _bin_digit | '2' - '7';
_dec_digit: _oct_digit | '8' - '9';
_hex_digit: _dec_digit | 'A' - 'F' | 'a' - 'f';
number: ['-' | '+'] '0' 'b' _bin_digit {_bin_digit | '_'}
    | ['-' | '+'] '0' 'o' _oct_digit {_oct_digit | '_'}
    | ['-' | '+'] _dec_digit {_dec_digit | '_'}
    | ['-' | '+'] '0' 'x' _hex_digit {_hex_digit | '_'};

_name_initial: 'A' - 'Z' | 'a' - 'z' | '_' | '~' | '!' | '@' | '#' | '$' | '%' | '^' | '&' | '*' | '-' | '_' | '+' | '=' | '?' | '/' | '.' | '\'';
_name_char: _name_initial | _dec_digit;
name: _name_initial {_name_char};

!whitespace: ' ' | '\t' | '\n' | '\r';
!comment: ';' {.} '\n';

<<>>
Schema: ExprList;
ExprList
    : Expr
    | ExprList Expr
    ;
ValList
    : Val
    | ValList Val
    ;
Val
    : string
    | number
    | name
    | Expr
    ;
Expr
    : "(" name Val Val ")"
    | "(" name Val ")"
    | "(" name ")"
    | "(" "." ValList ")"
    ;