This can produce unexpected results if you do not pay attention to the side effects of the expression 如果您没有注意表达式的副作用,则它可能会产生意外的结果。
This allows you to formally reason about program behavior , because the meaning of an expression depends only on the meaning of its subexpressions and not on the order of evaluation or side - effects of other expressions 这使您可以从形式上推断程序行为,因为表达式的意义只取决于其子表达式而不是计算顺序或者其他表达式的副作用。
For instance , an actual implementation need not evaluate part of an expression if it can deduce that its value is not used and that no side effects affecting the observable behavior of the program are produced 例如,如果某个具体实现可以推导出表达式中的某部分的值不会被用到,并且这一部分表达式的副作用不会对程序产生的可观察行为造成影响时,这个实现就无需对这部分表达式进行求值。
表达式: representation; expression的: 4次方是 The fourth power of 2 i ...副作用: side effect碘的副作用: iodine side effect函数的副作用: function's side effect教师的副作用: how teachers make children hate reading药物的副作用: side effects of pharmaceutical drugs疫苗的副作用: adverse vaccine effect有害的副作用: unwanted side effects表达式的: mathml表达式的值: values of expressions副作用,就是药品的副作用: warm house side effect表达式的等价: equivalence of expression表达式的范围: case表达式的简化: simplification of expression表达式的精度: precision in expression表达式的类型: type of expression麻醉药物的副作用: side effects from the use of anesthetics表达式的值是常量: expression value is constant (evc)表达式的值总是零: expression value is always zero (evaz)符号表达式的项: term in a symbolic expression面向表达式的语言: expression-oriented language通过中枢神经系统的副作用,中枢性副作用: central nervous system-mediated side effects药物的有害的副作用: the adverse effects of drugs表达式的类型必须为: type of expression must be boolean; type of expression must be integer