Scope functions (`let`, `apply`, `also`, `run`, `with`) — how do they differ?

Deep dive

Scope functions answer two questions:

• Do you want the context object as `this` (receiver) or as `it` (argument)?
• Do you want to return the object or the lambda result?

Quick cheatsheet:

• `let`: `it`, returns lambda result (great with null-safe calls).
• `apply`: `this`, returns receiver (configure/build object).
• `also`: `it`, returns receiver (side effects like logging).
• `run`: `this`, returns lambda result (compute using receiver).
• `with(x)`: like `x.run { ... }` but as a function (non-extension).

Common pitfalls

• Overusing scope functions and hurting readability.
• Using `apply` for side effects and forgetting it returns the receiver (not the computed value).