Dealing with Ambiguity There are two ways to remove ambiguity 1)Rewrite the grammar into a unambiguous grammar EE+T T TT*int int I(E) 口 Enforces precedence(优先级)of*over+ 口 Enforces left- associativity(左结合)of+and* 2) Declarations: instruct parser to pick desired parse trees a using %left, %right, %prec declarations7 Dealing with Ambiguity There are two ways to remove ambiguity: 1) Rewrite the grammar into a unambiguous grammar E E + T | T T T * int | int | ( E )  Enforces precedence（优先级） of * over +  Enforces left-associativity（左结合） of + and * 2) Declarations: instruct parser to pick desired parse trees  using %left, %right, %prec declarations