"immutable" is kind of overloaded term, but what it means in this context is an object itself doesn't mutate when you want to change a value (basically value se

"immutable" is kind of overloaded term, but what it means in this context is an object itself doesn't mutate when you want to change a value (basically value semantics[0] instead of reference semantics[1]) for example (pseudocode) var newUser = Person(name: "some guy", age: 0) // newUser is replaced with a new object that is // initialized with field.name and previous age (0) // the old object is discarded newUser.name = field.name // object is passed as copy-on-write, assuming a 1 sec delay // it will print the objects values at this point in time // (age: 0) even if altered later async(after:1) { print(newUser.age) } // prints 0 // age was changed to 32 a nanosecond later, // but now a new object again is initialized // instead of mutated newUser.age = 32 print(newUser.age) // prints 32 ---------- output: 32 0 [0] https://en.wikipedia.org/wiki/Value_semantics https://en.wikipedia.org/wiki/Value_semantics [1] https://stackoverflow.com/questions/27084007/what-is-value-and-reference-semantics-and-the-difference https://stackoverflow.com/questions/27084007/what-is-value-a...