Jison：二進制操作語法衝突

Question

在試圖建立我的Jison語法我有：

%left 'OR' 'AND' 

%% 

Expression: 
    Operation 
; 

Operation: 
    Expression Operator Expression {$$ = new yy.LogicalExpression($2, $1, $3)} 
; 

Operator: 
    'AND' 
| 'OR' 
; 

但是，這導致以下衝突的消息：

Conflict in grammar: multiple actions possible when lookahead token is OR in state 6 
- reduce by rule: Operation -> Expression Operator Expression 
- shift token (then go to state 5) 
Conflict in grammar: multiple actions possible when lookahead token is AND in state 6 
- reduce by rule: Operation -> Expression Operator Expression 
- shift token (then go to state 4) 

States with conflicts: 
State 6 
    Operation -> Expression Operator Expression . #lookaheads= $end OR AND 
    Operation -> Expression .Operator Expression 
    Operator -> .AND 
    Operator -> .OR 

當我更換消除Operator非而不是直接寫出表達模式：

%left 'OR' 'AND' 

%% 

Expression: 
    Operation 
; 


Operation: 
    Expression 'AND' Expression {$$ = new yy.LogicalExpression($2, $1, $3)} 
| Expression 'OR' Expression {$$ = new yy.LogicalExpression($2, $1, $3)} 
; 

我沒有這樣的錯誤或者，爲什麼第一個語法有衝突，但不是第二個？他們似乎相當於我的理解。

提前致謝！

Answer 1

預測太多，但第一種形式無論如何都是錯誤的。第二種形式是正確的。您需要爲AND和OR以及所有其他操作員編寫單獨的作品。否則，您無法獲得運算符優先級。