Access-Control.md

Access Control

// most open
open        class UITableView {}
public      protocol UITableViewDataSource {}
internal    class SomeInternalClass {}
fileprivate class SomeFilePrivateClass {}
private     class SomePrivateClass {}
// most closed

• Default is internal
• Open access is least restrictive. Private is most.

class SomeInternalClass {}              // implicitly internal
let someInternalConstant = 0            // implicitly internal

open & public

Open access and public access enable entities to be used within any source file from their defining module, and also in a source file from another module that imports the defining module. You typically use open or public access when specifying the public interface to a framework

Diffrence between open & public?

• Public classs / methods can only be subclassed / overridden within the module they are defined.
• Open classes / methods can be subclassed / overriden within any module that imports them
• So open is beyond the module. Public is more restrictive as it's within.

internal

• enabled entities within the module to extend / override but not those without. Use internal when defining an apps internal structure.

file private

• limits extending / overriding to that file

private

• restricts use to that closing declaration and to extensions that are in the same file

Public - anyone can use Internal - within that module (default) File-private - within that file Private - the classes and sub entities

Links that help

• Swift Lanaguage Guide - Access Control