Literals

Literals are used to represent values in the source code. They are used to initialize variables, to pass arguments to functions, etc.

Integer literals

Integer literals represent an integer value. They can be written in decimal, hexadecimal, octal or binary notation.

INTEGER_LITERAL :
     DECIMAL_LITERAL
     | HEXADECIMAL_LITERAL
     | OCTAL_LITERAL
     | BINARY_LITERAL

DECIMAL_LITERAL : DEC_DIGIT^*

HEXADECIMAL_LITERAL : ( 0x | 0X )DEC_DIGIT⁺

OCTAL_LITERAL : ( 0o | 0O )OCT_DIGIT⁺

BINARY_LITERAL : ( 0b | 0B )BIN_DIGIT⁺

BIN_DIGIT : [ 0 - 1 ]

OCT_DIGIT : [ 0 - 7 ]

HEX_DIGIT : [ 0 - 9 a - f A - F ]

DEC_DIGIT : [ 0 - 9 ]

Floating-point literals

Floating-point literals represent a floating-point value. They can be written in decimal or hexadecimal notation.

FLOATING_LITERAL :
     | DECIMAL_LITERAL . DECIMAL_LITERAL^?
     | . DECIMAL_LITERAL
     | DECIMAL_LITERAL ( . DECIMAL_LITERAL )^? EXPONENT

EXPONENT := ( e|E ) ( +|- )^? DECIMAL_LITERAL

String and character literals

Character literals represent a single character. String literals represent a sequence of characters.

Character literals

CHAR_LITERAL : ' CHAR_FRAGMENT^? '

CHAR_FRAGMENT :
     ~[ ' \ \n \r \t ]
     | QUOTE_ESCAPE
     | ASCII_ESCAPE
     | UNICODE_ESCAPE

QUOTE_ESCAPE : \' \"

ASCII_ESCAPE : \x OCT_DIGIT HEX_DIGIT | \n | \r | \t | \\ | \0

UNICODE_ESCAPE : \u{ HEX_DIGIT^[1,6] }

String literals

STRING_LITERAL : " STRING_FRAGMENT^* "

STRING_FRAGMENT :
     ~[ " \ \n \r \t ]
     | QUOTE_ESCAPE
     | ASCII_ESCAPE
     | UNICODE_ESCAPE