Terminology: separating Data, State and Logic

Question

Is there a general term for the software paradigm/principle where there is a clear separation between Data, State and Logic (Data - 'information' only, immutable with value semantics, State - 'storage' of Data only with clearly defined access/mutation mechanisms, Logic - pure stateless functionality that can mutate the States) ?

This is as opposed to OOP where Data State and Logic are coupled in a 'class'

I see this separation referred to in many places (especially in clojure) but I couldn't find a single name/term for it .. sometime 'functional' is used but there are ie many functional languages (ie Javascript) without such separation ?

(I am not sure if any other Tags are relevant here)

Answer 1

They aren't different things.

Consider a pure functional language. Everything is a function, and I do mean everything. Its called Lambda Calculus and it is Turing Complete.

In this language: values, state, and behaviour are all just functions.

Even in JavaScript the concept is loose. The object is really just the stack frame of a function that decided to return its stack frame. And that is true of everything except a handful of primitives. (Implementations of course will do what they do, we are considering at the language level.)

Consider a String

• It is a value (a single state)
• It is a modifiable state, allowing characters to be edited (depending on language, but even with immutable states, it still appears to permit editing which is all we care about from a first hand usage perspective, as variables can be shared.)
• It is a behaviour - a mini program for how to draw glyphs on a screen.

So which one is it?

Terminology

In a layman perspective. You are probably looking for

• a functional/logic language for value/behaviour split
• a imperative language for state/behaviour split

But that is only a surface level understanding.