SmoothOperators

A tiny collection of (more or less) useful Swift operators.

Use with SPM

dependencies: [
    // Dependencies declare other packages that this package depends on.
    ...
    .package(url: "https://github.com/Pyroh/SmoothOperators.git", .upToNextMajor(from: "0.4.0")),
    ...
],

Numeric manipulation oriented operators

Adds back prefixed and postfixed ++ and -- operators.
Introduces postfixed + and - operators that respectively return value + 1 and value - 1.
Adds an exponent operator **.

Comparison operator

Features a variant for ==, !=, >, <, >=, <= respectively ==?, !=?, >?, <?, >=?, <=? that return an optional value instead of a boolean one. If the outcome should have been true the left value is returned in a form of an optional. If the outcome should have been false nil is returned.

5 ==? 5 // Optional(5)
5 ==? 6 // nil

5 !=? 6 // Optional(5)
5 !=? 5 // nil

5 >? 4 // Optional(5)
5 >? 6 // nil

5 >=? 5 // Optional(5)
5 >=? 6 // nil

5 <? 6 // Optional(5)
5 <? 4 // nil

5 <=? 5 // Optional(5)
5 <=? 4 // nil

Other operators

Transform and reassign: `<-`

This infix operator take take the left variable, transform it using the closure at its right and put the resulting value back in the left variable.

var a: Int = 42

a <- { $0 - 2 } // a == 40

func divideByTwo(_ value: Int) -> Int {
value / 2
}

a <- divideByTwo // a == 20

Boolean cast for optionals: `!!`

This prefixed operator returns false if the value its attached to is nil. true otherwise.

let a: Int? = 5
let b: Int? = nil

!!a // true
!!a // false

NaN-Coalescing `??`

Is the same as the nil-coalescing operator but for floating point values. These values can be NaN.
This operator returns the value if it's not NaN otherwise it returns the default value.

let a: Double? = 42
let b: Double? = nil
let c: Double = 42
let d: Double = .nan
let e: Double? = .nan

a ?? 0 // 42.0
b ?? 0 // 0.0
c ?? 0 // 42.0
d ?? 0 // 0.0
(e ?? 0) ?? 1 // 1.0

Empty-Coalescing `??`

Is the same as the nil-coalescing operator but for collections. This operator returns the collection if it's not empty otherwise it returns the default collection.

Optional assignment `?=`

Assign the right hand side value to the left hand side optional if its nil. a ?= 42 is equivalent to a = a ?? 42 for any var a: Int?.

License

See LICENSE.