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37 lines
1.6 KiB
Markdown
37 lines
1.6 KiB
Markdown
# iOSProgrammingGuidelines
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## Swift
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### Type vs instance methods
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If a method is independent of instance state it should be declared as type method, preferably by using `static` keyword (or `class` in case when the method is designed to be overridden in a subclass).
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> This is to avoid methods giving a false impression that they are dependent on the instance state while in fact they are not.
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### Controlling subclassing behavior
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Subclassing behavior should be designed with maximal hermetization principle in mind - choosing most restrictive access level possible.
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Declare class `final` unless you explicitly design it to be inheritable. For non final class declare all instance members as `final` and type members as `static` except for those you explicitly design for overriding.
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When designing a module prefer `public` for non final class unless you explicitly design it to be inheritable by external clients. For `open` class prefer `public` for members except for those you explicitly design for overriding by external clients.
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> Every point that can be overridden increases complexity, thus it should always be a conscious choice to add it.
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### Avoid force unwrapping
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Use `guard` and `fatalError()` instead of force unwrapping to clarify your intent.
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```swift
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guard let value = optionalValue else { fatalError("reason why value must be present") }
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```
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> This is to avoid situations in which reason for force unwrapping is undocumented.
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### Place noop comment in functions left empty by intention
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```swift
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func didDeliver(parcel: Parcel) {
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// noop
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}
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```
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> This is to make clear function is empty by intention and not by mistake
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