DarkoDamjanovic/ifSome

ifSome

ifSome is an attempt to create an alternative functional shorthand syntax of optional binding (if let) in Swift. Use it like this:

let text: String? = "txet emoS"  

text.ifSome{ print($0) } 
 
text.ifSome {
    let reversed = String($0.characters.reverse())
    print(reversed) // "Some text"
}

It resembles also what meanwhile is available in Kotlin as the let syntax:

private fun load() {
    product.let {
        viewModel.load(it)
    }
}

If the String is not nil the closure will be called and the Optional will be automatically unwrapped inside the closure. ifSome is not intended as an replacement for if let but an alternative in some cases.

Alternatively also this syntax is possible:

let optional: Int? = 5
optional.ifSome{ unwrapped in print(unwrapped) }

Most of the time if let (or guard) is used in Swift to check for nil, which is not always the best solution.

Another solution is:

if text != nil {
    print(text!) // forced unwrapping needed
}

But this needs forced unwrapping, which generally should be avoided if possible. Better would be:

text.ifSome{ print($0) }

Another way to check for nil is optional chaining:

let text: String? = "Some text"
text?.removeAll()

But optional chaining only allows calling functionality on the object, it is not possible to use the object like with if let or ifSome.

ifNone

Just for the sake of completness also an ifNone method is included.

let someText: String? = nil
someText.ifNone { print("someText is really nil") }

The trailing ifNone closure is only called if the value is nil.

Disadvantages of ifSome

• only possible to use on one Optional, if let allows unwrapping multiple at a time
• access to the unwrapped Optional over $0 syntax
• not possible to unwrap the Optional as mutable var (at least I didn't found out how to do it)

Installation

ifSome is an extension of the Swift Optional enum. Just add the file "Optional+ifSome.swift" to your project.