如何在yacc語法中刪除shift-reduce衝突？

Question

我有以下語法：

Expression 
    : SimpleExpression {$$ = $1;}; 
    | SimpleExpression LTnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    | SimpleExpression LEnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    | SimpleExpression EQnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    | SimpleExpression NEnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    | SimpleExpression GEnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    | SimpleExpression GTnum SimpleExpression 
     { MkLeftC($1, $2); $$ = MkRightC($3, $2); } 
    ; 

SimpleExpression 
    : PLUSnum Term op_terms 
     { $$ = MakeTree(AddOp,$3,$2); } 
    | MINUSnum Term op_terms 
     { $$ = MakeTree(SubOp,$3,$2); } 
    ; 

op_terms 
    : PLUSnum Term 
     { $$ = MakeTree(AddOp,NullExp(),$2); } 
    | PLUSnum Term op_terms 
     { $$ = MakeTree(AddOp,$3,$2); } 
    | MINUSnum Term 
     { $$ = MakeTree(SubOp,NullExp(),$2); } 
    | MINUSnum Term op_terms 
     { $$ = MakeTree(SubOp,$3,$2); } 
    | ORnum Term 
     { $$ = MakeTree(OrOp,NullExp(),$2); } 
    | ORnum Term op_terms 
     { $$ = MakeTree(OrOp,$3,$2); } 
    ; 

我得到的y.output文件中的以下移減少衝突：

51: shift/reduce conflict (shift 74, reduce 57) on GTnum 
51: shift/reduce conflict (shift 75, reduce 57) on NEnum 
51: shift/reduce conflict (shift 76, reduce 57) on EQnum 
51: shift/reduce conflict (shift 77, reduce 57) on GEnum 
51: shift/reduce conflict (shift 78, reduce 57) on LEnum 
51: shift/reduce conflict (shift 79, reduce 57) on LTnum 
state 51 
    Expression : SimpleExpression . (57) 
    Expression : SimpleExpression . LTnum SimpleExpression (58) 
    Expression : SimpleExpression . LEnum SimpleExpression (59) 
    Expression : SimpleExpression . EQnum SimpleExpression (60) 
    Expression : SimpleExpression . NEnum SimpleExpression (61) 
    Expression : SimpleExpression . GEnum SimpleExpression (62) 
    Expression : SimpleExpression . GTnum SimpleExpression (63) 

我需要消除這些衝突的幫助。我在這裏做錯了什麼？我試圖設置優先規則，但它們似乎在這裏似乎不起作用。有任何想法嗎？

Answer 1

奇怪的語法。它應該是這種形式：

Expression 
    : SimpleExpression {$$ = $1;}; 
    | Expression LTnum SimpleExpression 
    | Expression LEnum SimpleExpression 
    | Expression EQnum SimpleExpression 
    | Expression NEnum SimpleExpression 
    | Expression GEnum SimpleExpression 
    | Expression GTnum SimpleExpression 
    ; 

即使用左遞歸。

也是奇怪的樹。它應該是一般形式：

$$ = MkBinaryNode($1,$2,$3);