Pure Function in mathematical sense is a function that has no side effect, does not change the state of the program and always produces the same results when given the same arguments. I think that pure function is adhered to the concept of orthogonality#.
It is emphasised heavily in #202203061121.
This eventually makes the function #pure.
A function with the identifier inline in C is called an Inline Function. Inline Function makes no function call, instead they are like macros where the place that the function called will be replaced by the function definition or the code that is inside the function. Since inline function doesn’t introduce #overhead, it is great to inline short functions especially 202202081524#. Always prefer Inline Function over function-like macro.
Functional Programming focus on 202202081524# and avoids mutable state. To change the value, most functional programming languages use new copy to change value, but this could be expensive.
Note: Avoid global variable and use 202202081524 as much as possible.
Clojure is a #functional Lisp programming language. Although like other functional programming it emphasises on 202202081524, Clojure also allows impure functions. 202203061126# and keywords could act as functions too.