Negates any boolean expression which can include keywords , such as like , null , between , in , and exists 对任何布尔表达式它可包含如like null between in和exists这样的关键字求反。
Assertions represent boolean expressions that the programmer believes to be true at specific points in the program 断言表示为一些布尔表达式,程序员相信在程序中的某个特定点该表达式的值为真。
Statement can be used to execute one of two blocks of program statements , depending on the value of a particular boolean expression 语句可以如何用于根据一个特定布尔表达式的值,来执行两个程序语句块中的其中一个。
On the other hand , it is expressible as a boolean expression if you accept including function calls in the boolean expression 但换个角度,如果你允许在布尔表达式中植入包含函数调用,则它就是一个布尔表达式可表述的属性。
Boolean expressions are intended precisely to express runtime true or false properties ? properties that at any point in the execution may hold or not hold 布尔表达式的设计意图就是表达运行时值为真或假的属性,在某个时刻判断此属性的值就可以决定执行是否继续。
Boolean expressions are r nintended precisely to express runtime true or false r nproperties ? properties that at any point in the execution may hold or r nnot hold 布尔表达式的设计意图就是表达运行时值为真或假的属性,在某个时刻判断此属性的值就可以决定执行是否继续。
What is quite easy to express with boolean expressions , for example , is a property that if you ' re adding an element at the end of a list , the last element of the list is now the one that you just added 举例来说,如果你将一个元素增加到列表末尾,该列表当前的最后一个元素就是你刚刚增加的元素。
But , because they are strictly functional boolean expressions , they are limited in their expressiveness - how would we encode our first rule for stacks into an assertion , for instance 但是,由于它们是严格的函数布尔表达式,它们被限制在自己的表达中例如,我们将如何把堆栈的第一条规则编写到断言中?
This program creates truth tables from boolean expressions . i believe that it ' s very useful for computer science students who learning boolean algebra and predicate logic ( like my self ) 这个程序从布尔表达式中创建真实的表格。我相信对于学习布尔代数学和谓词逻辑的计算机科学学生(像我自己这样的)来说它是非常有用的。
The second occasion where boolean expressions may seem restrictive is one that scares most people who have looked at the issue from a theoretical perspective : the language of boolean expressions is relatively limited and doesn ' t have first - order predicate calculus 很多人从理论角度考察时,又惊惧地发现布尔表达式形似柔弱的第二种情况:使用布尔表达式的语言有局限性,因为不具备一阶谓词演算特性。