referential transparency

Referential transparency is a concept in programming and mathematics where an expression can be replaced with its value without changing the program’s behavior. Essentially, if you see a function or variable, you can substitute it with the result it produces without affecting the outcome. This makes reasoning about code simpler and more predictable, as it ensures consistency. For example, if you define a variable as "5," you can replace all instances of it in calculations with "5," and the outcome will remain the same. This property is key in functional programming, promoting easier debugging and better maintainability.