gistfile1.txt

grammar Grammar;

fragment Uppercase           : [A-Z] | '$' | '_'                ;
fragment Lowercase           : [a-z]                            ;
fragment Letter              : Uppercase | Lowercase            ;
fragment Operator            : [\u0020-\u007F]+                 ;
fragment Body                : (Letter | [0-9])* ('_' Operator) ;
fragment Decimal             : '0' | [1-9] [0-9]*               ;
fragment Hexadecimal         : '0' 'x' [0-9A-Fa-f]+             ;
fragment Octal               : '0' [0-7]+                       ;
fragment Exponent            : [Ee] ('+' | '-')? [0-9]+         ;
fragment Float               : [DdFf]                           ;
fragment SingleQuotationMark : '\u2019' | '\u0022' | '\u0027'   ;
fragment DoubleQuotationMark : '\u0022' | '\u201C' | '\u201D'   ;

VARIABLE   : Lowercase Body                                                ;
IDENTIFIER : Uppercase Body | VARIABLE | Operator                          ;
INTEGER    : (Decimal | Hexadecimal | Octal) ('L' | 'l')                   ;
FLOAT      : [0-9]+ '.' [0-9]* Exponent? Float?
           |        '.' [0-9]+ Exponent? Float?
           | [0-9]+            Exponent  Float?
           | [0-9]+            Exponent? Float                             ;
BOOLEAN    : 'true' | 'false'                                              ;
CHARACTER  : SingleQuotationMark [\u0080-\ufffe]  SingleQuotationMark      ;
STRING     : DoubleQuotationMark [\u0080-\ufffe]+ DoubleQuotationMark      ;
NEWLINE    : ';'
           | [\u000A-\u000D] | '\u000D\u000A' | '\u0085' | [\u2028-\u2029] ;
WHITESPACE : ('\u0020' | '\u0009' | '\u000D' | '\u000A') -> skip           ;
COMMENT    : ('/*' .*? '*/' | '//' .*? NEWLINE)          -> skip           ;

literal     : ('-')? INTEGER
            | ('-')? FLOAT
            |        BOOLEAN
            |        CHARACTER
            |        STRING
            |        'null'                          ;
identifiers : IDENTIFIER (',' IDENTIFIER)*           ;
expression  : (IDENTIFIER | '_') '\u21D2' expression
            | expression1                            ;
expression1 : 'if' expression (NEWLINE)? expression
              ((NEWLINE)? 'else' expression)?
            | postfix                                ;
postfix     : infix (IDENTIFIER (NEWLINE)?)?         ;
infix       : prefix
            | infix IDENTIFIER (NEWLINE)? infix      ;
prefix      : ('-' | '+' | '~' | '!')? simple        ;
simple      : simple1 ('_')?                         ;
simple1     : literal
            | '_'
            | '(' (expression)? ')'                  ;