【问题】
用antlrworks去调试antlr的语法文件，代码为：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | grammar DDParserDemo;options { output = AST; ASTLabelType = CommonTree; // type of $stat.tree ref etc...}//NEWLINE : '\r'? '\n' ;//NEWLINE : '\r' '\n' ;fragment NEWLINE : '\r'? '\n' ;ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;FLOAT : ('0'..'9')+ '.' ('0'..'9')* EXPONENT? | '.' ('0'..'9')+ EXPONENT? | ('0'..'9')+ EXPONENT ;COMMENT : '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;} | '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;} ;WS : ( ' ' | '\t' | '\r' | '\n' ) {skip();} ;STRING : '"' ( ESC_SEQ | ~('\\'|'"') )* '"' ;CHAR: '\'' ( ESC_SEQ | ~('\''|'\\') ) '\'' ;fragmentEXPONENT : ('e'|'E') ('+'|'-')? ('0'..'9')+ ;fragmentHEX_DIGIT : ('0'..'9'|'a'..'f'|'A'..'F') ;fragmentESC_SEQ : '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\') | UNICODE_ESC | OCTAL_ESC ;fragmentOCTAL_ESC : '\\' ('0'..'3') ('0'..'7') ('0'..'7') | '\\' ('0'..'7') ('0'..'7') | '\\' ('0'..'7') ;fragmentUNICODE_ESC : '\\' 'u' HEX_DIGIT HEX_DIGIT HEX_DIGIT HEX_DIGIT ;fragmentDIGIT : '0'..'9';//FAKE_TOKEN : '1' '2' '3';/*DECIMAL_VALUE : '1'..'9' DIGIT*;*/DECIMAL_VALUE : DIGIT*;HEX_VALUE : '0x' HEX_DIGIT+;/* startParse : (identification)+;*/startParse : (identification)+;identification : definiton WS* ','? WS* -> definiton ; definiton : (ID)^ ('\t'!|' '!)+ (DECIMAL_VALUE | HEX_VALUE) ; |
然后去
Generate -> Generate Code
结果虽然是可以正常编译，以及后续的正常调试。
但是却出现警告：
[13:56:55] warning(200): DDParserDemo.g:87:28: As a result, alternative(s) 2 were disabled for that input Decision can match input such as "WS" using multiple alternatives: 1, 2 As a result, alternative(s) 2 were disabled for that input |
很明显，该警告，对应的代码为：
1 2 3 4 5 | WS : ( ' ' | '\t' | '\r' | '\n' ) {skip();} |
此处想要完全搞懂，此处的警告的确切含义。
如果可以的话，尽量消除此警告。
【解决过程】
1.
转载请注明：在路上 » 【未解决】antlr语法警告：warning: Decision can match input such as "WS" using multiple alternatives: 1, 2