Literals

literal ::= nil-literal |
            boolean-literal |
            integer-literal |
            real-literal |
            atom-literal |
            string-literal

nil-literal ::= 'nil'

boolean-literal ::= 'true' |
                    'false'

integer-literal ::= binary-integer-literal |
                    octal-integer-literal |
                    decimal-integer-literal |
                    hexadecimal-integer-literal
binary-integer-literal ::= '0' [bB] binary-digit ('_'* binary-digit)*
binary-digit ::= [0-1]
octal-integer-literal ::= '0' [oO] octal-digit ('_'* octal-digit)*
octal-digit ::= [0-7]
decimal-integer-literal ::= decimal-digit ('_'* decimal-digit)*
decimal-digit ::= [0-9]
hexadecimal-integer-literal ::= '0' [xX] hexadecimal-digit ('_'* hexadecimal-digit)*
hexadecimal-digit ::= [0-9a-fA-F]

real-literal ::= real-part '.' real-part ([eE] [+-]? real-part)?
real-part ::= decimal-digit ('_'* decimal-digit)*

atom-literal ::= ':' (upper-identifier |
                      lower-identifier |
                      discard-identifier)

string-literal ::= regular-string-literal |
                   verbatim-string-literal |
                   block-string-literal

regular-string-literal ::= '"' ([^#xa#xd#x85#x2028#x2029"\] |
                                regular-string-escape-sequence)* '"'
regular-string-escape-sequence ::= '\' (regular-string-escape-simple |
                                        regular-string-escape-unicode)
regular-string-escape-simple ::= [0aAbBeEfFnNrRtTvV"\]
regular-string-escape-unicode ::= [uU] hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit

verbatim-string-literal ::= '"""' '"'* [^#xa#xd#x85#x2028#x2029]+ '"""' '"'*

block-string-literal ::= '"""' '"'* white-space* line-break block-string-line white-space* '"""' '"'*
block-string-line ::= [^#xa#xd#x85#x2028#x2029]* line-break