swift-guide/Naming.md

Naming

In general, follow the official guidelines.

Conventions

Naming a file

There's no three-letter prefix in Swift file naming. For example, if an Objective-C file named XYZEvent.m is to be converted to Swift, it should be renamed to Event.swift.

Naming a class or a protocol available in Objective-C

Provide a pre-fixed Objective-C name before the class or protocol definition.

Example

@objc class Event {
    // bad: exported to Objective-C as class Event without a prefix
}

@objc(XYZEvent)
class Event {
    // good
}

Naming a protocol

There is no need to add a prefix to a Swift protocol in order to distinguish it from a Swift class or struct.

• Protocols that describe what something is should read as nouns (e.g. Collection).

• Protocols that describe a capability should be named using the suffixes able, ible, or ing (e.g. Equatable, ProgressReporting)."

Example

protocol IFooEventHandler {
    // bad: the "I" prefix is not necessary
}

protocol FooEventHandler {
    // bad: "er" is not a good suffix for a protocol
}

protocol FooEventHandling {
    // good
}