Referential transparency https://en.wikipedia.org/wiki/Referential_transparency https://en.wikipedia.org/wiki/Referential_transparency > Referential transpare

Referential transparency https://en.wikipedia.org/wiki/Referential_transparency https://en.wikipedia.org/wiki/Referential_transparency > Referential transparency and referential opacity are properties of parts of computer programs. An expression is called referentially transparent if it can be replaced with its corresponding value (and vice-versa) without changing the program's behavior.[1] This requires that the expression be pure, that is to say the expression value must be the same for the same inputs and its evaluation must have no side effects. An expression that is not referentially transparent is called referentially opaque. > In mathematics all function applications are referentially transparent, by the definition of what constitutes a mathematical function. However, this is not always the case in programming, where the terms procedure and method are used to avoid misleading connotations. In functional programming only referentially transparent functions are considered. Some programming languages provide means to guarantee referential transparency. Some functional programming languages enforce referential transparency for all functions.