When is it better to use value types, and in which cases - reference types?

Value types (e.g., structures, enumerations, tuples) are copied when passed or assigned. Changes to one copy do not affect others.

Reference types (e.g., classes, closures, functions) pass a reference to the same instance. Changes made through one reference are reflected in all other references to the same object.

It is better to use value types:

• When independence of copies is important.
• For small, simple data structures where copying is cheaper than managing a reference type.
• To ensure thread safety in a concurrent environment (changes do not affect other threads).
• When guaranteed immutability after creation is required.

It is better to use reference types:

• When a single shared instance of an object is needed, accessible from different parts of the code.
• For large, complex data structures or objects where copying would be inefficient.
• When polymorphism or inheritance is required (classes support these features).
• For objects with lifecycle management (e.g., thanks to ARC).
• When shared mutability of state between parts of the application is needed.