我收到錯誤:no viable alternative at input 'mult'
當我試圖解析輸入:div(mean(mult(field_a, field_b)), sum(field_b))
。ANTLR - 輸入時沒有可行的替代方法
這裏是我的語法:
grammar Analytics;
start: expr | stat;
expr
: UNARY_EXPR '(' (stat | expr | NUMBER) ')' #unaryExpr
| BINARY_EXPR '(' (stat | expr | constant) ',' (stat | expr | constant) ')' #binaryExpr
| MULTIPLE_EXPR '(' (stat | expr | constant) ',' (stat | expr | constant)+ ')' #multipleExpr
;
stat
: UNARY_STAT '(' (operation | field) ')' #unaryStat
| BINARY_STAT '(' (operation | field) ',' (operation | field) ')' #binaryStat
;
operation
: UNARY_OPERATION '(' operation ')' #unaryOperation
| BINARY_OPERATION '(' operation ',' operation ')' #binaryOperation
| MULTIPLE_OPERATION '(' operation ',' operation+ ')' #multipleOperation
| field #fieldOperation
;
constant: NUMBER;
field: IDENTIFIER;
UNARY_EXPR: 'neg' | 'const_num' | 'rev' | 'miss' | 'const_date' | 'const_str';
BINARY_EXPR: 'div' | 'pow' | 'log';
MULTIPLE_EXPR: 'add' | 'mult' | 'date_math' | 'concat';
UNARY_STAT: 'count' | 'missing' | 'min' | 'max' | 'stddev' | 'sum' | 'sumofsquares' | 'mean' | 'unique' | 'median' |
'const_num' | 'neg' | 'abs';
BINARY_STAT: 'add' | 'mult' | 'div' | 'pow' | 'log';
UNARY_OPERATION: 'neg' | 'rev' | 'const_date' | 'const_str';
BINARY_OPERATION: 'div' | 'pow' | 'log' | 'miss';
MULTIPLE_OPERATION: 'add' | 'mult' | 'date_math' | 'concat';
OPEN_BRACKET: '(';
CLOSE_BRACKET: ')';
COMMA: ',';
NUMBER: ('0'..'9')+ ('.' ('0'..'9')+)? ;
IDENTIFIER : [a-zA-Z][a-zA-Z0-9_]*;
WS : (' ' | '\t')+ -> skip;
什麼我錯在這裏做的是導致其不符合mult
? 是否有我可以用來調試此錯誤的建議方法?
另外,如何檢查每個規則匹配的選項? 例如,我得到的toStringTree()
輸出是:(start (expr div ((stat mean (mult (field) , field)) , sum (field))))
。我怎麼能說,第一個expr
規則是匹配BINARY_EXPR '(' (stat | expr | constant) ',' (stat | expr | constant) ')'
而不是UNARY_EXPR '(' (stat | expr | NUMBER) ')'
?