感谢antlr4，让事情变得容易
lexer grammar BeetlLexer;
If:'if';
For:'for';
Else:'else';
While:'while';
Switch:'switch';
Select:'select';
Return:'return';
Break:'break';
Continue:'continue';
Var:'var';
Directive:'DIRECTIVE'|'directive';
Case:'case';
Default:'default';
Try:'try';
Catch:'catch';
LEFT_BRACE:'{';
RIGHT_BRACE:'}';
LEFT_PAR:'(';
RIGHT_PAR:')';
LEFT_SQBR:'[';
RIGHT_SQBR:']';
INCREASE:'++';
DECREASE:'--';
VIRTUAL:'.~';
ADD:'+';
MIN:'-';
MUlTIP:'*';
DIV:'/';
MOD:'%';
EQUAL:'==';
NOT_EQUAL:'!=';
ASSIN:'=';
LARGE:'>';
LESS:'<';
NOT:'!';
AND:'&&';
OR:'||';
QUESTOIN:'?';
AT:'@';
NULL:'null';
TRUE:'true';
FALSE:'false';
END:';';
COMMA:',';
COLON:':';
PERIOD:'.';
FOR_IN:'in';
LEFT_TOKEN:'<<';
RIGHT_TOKEN:'>>';
LEFT_TEXT_TOKEN :'<$';
// LEXER
HexLiteral : '0' ('x'|'X') HexDigit+ IntegerTypeSuffix? ;
DecimalLiteral : ('0' | '1'..'9' '0'..'9'*) IntegerTypeSuffix? ;
OctalLiteral : '0' ('0'..'7')+ IntegerTypeSuffix? ;
fragment
HexDigit : ('0'..'9'|'a'..'f'|'A'..'F') ;
fragment
IntegerTypeSuffix : ('l'|'L') ;
FloatingPointLiteral
: ('0'..'9')+ '.' ('0'..'9')* Exponent? FloatTypeSuffix?
| '.' ('0'..'9')+ Exponent? FloatTypeSuffix?
| ('0'..'9')+ Exponent FloatTypeSuffix?
| ('0'..'9')+ FloatTypeSuffix
| ('0x' | '0X') (HexDigit )*
('.' (HexDigit)*)?
( 'p' | 'P' )
( '+' | '-' )?
( '0' .. '9' )+
FloatTypeSuffix?
;
fragment
Exponent : ('e'|'E') ('+'|'-')? ('0'..'9')+ ;
fragment
FloatTypeSuffix : ('f'|'F'|'d'|'D') ;
CharacterLiteral
: '\'' ( EscapeSequence | ~('\''|'\\') ) '\''
;
StringLiteral
: '"' ( EscapeSequence | ~('\\'|'"') )* '"'
;
fragment
EscapeSequence
: '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\')
| UnicodeEscape
| OctalEscape
;
fragment
OctalEscape
: '\\' ('0'..'3') ('0'..'7') ('0'..'7')
| '\\' ('0'..'7') ('0'..'7')
| '\\' ('0'..'7')
;
fragment
UnicodeEscape
: '\\' 'u' HexDigit HexDigit HexDigit HexDigit
;
Identifier
: Letter (Letter|JavaIDDigit)*
;
/**I found this char range in JavaCC's grammar, but Letter and Digit overlap.
Still works, but...
*/
fragment
Letter
: '$' |
'A'..'Z' |
'_' |
'a'..'z' |
'À'..'Ö' |
'Ø'..'ö' |
'ø'..'ÿ' |
'Ā'..'' |
''..'' |
'㌀'..'㍿' |
'㐀'..'㴭' |
'一'..'鿿' |
'豈'..''
;
fragment
JavaIDDigit
: '0'..'9' |
'٠'..'٩' |
'۰'..'۹' |
'०'..'९' |
'০'..'৯' |
'੦'..'੯' |
'૦'..'૯' |
'୦'..'୯' |
'௧'..'௯' |
'౦'..'౯' |
'೦'..'೯' |
'൦'..'൯' |
'๐'..'๙' |
'໐'..'໙' |
'၀'..'၉'
;
COMMENT_OPEN
: '/*' ->mode(ISLAND),channel(HIDDEN)
;
mode ISLAND;
PARAS:'@' Identifier ':' Identifier ('.' Identifier)* ;
WS1 : [ \r\t \n]+ -> channel(HIDDEN);
COMMENT_END: '*/' -> mode(DEFAULT_MODE),channel(HIDDEN)
;
WS : [ \r\t \n]+ -> channel(HIDDEN)
;
LINE_COMMENT
: '//' ~[\r\n]* '\r'? '\n' -> channel(HIDDEN)
;
