and,or,xor等位运算中缀函数并非严格意义上的运算符,它们的执行顺序与其他中缀函数相同,即从左到右,因此以下两行代码是等价的: a or b and c or d and e (((a or b) and c) or d) and e Also note that the precedence of the infix functions is lower than that of operators: 1 + 2 and 3 + 4 (1 + 2) and (3 + 4)