Editing Value (computer science) (section)

{{short description|Expression in computer science which cannot be evaluated further}}
{{refimprove|date=August 2009}}
In [[computer science]] and [[software programming]], a '''value''' is the representation of some entity that can be manipulated by a program. The members of a [[type (computer science)|type]] are the values of that type.{{sfn|Mitchell|1996|p=9}} 

The "value of a variable" is given by the corresponding [[Map (computer science)|mapping]] in the [[environment (type theory)|environment]].<ref>{{Cite book |last1=Aho |first1=Alfred V. |title=Compilers: Principles, Techniques, and Tools |last2=Lam |first2=Monica S. |last3=Sethi |first3=Ravi |last4=Ullman |first4=Jeffrey D. |year=1986 |publisher=Addison-Wesley Publishing Company |isbn=0-201-10088-6}}</ref> In languages with [[assignable variable]]s, it becomes necessary to distinguish between the ''r-value'' (or contents) and the ''l-value'' (or location) of a variable.{{sfn|Mitchell|1996|pp=389–390}}

In [[Declarative programming|declarative]] (high-level) languages, values have to be [[referential transparency|referentially transparent]]. This means that the resulting value is independent of the location of the expression needed to compute the value. Only the contents of the location (the bits, whether they are 1 or 0) and their interpretation are significant.{{Citation needed|date=March 2011}}