Packages and Modules

Namespace Types

A type can group related helpers so callers use a clear prefix.

Group helpers under a type

width
namespace_types.swift
Replay: real traced execution (multi-file project)
enum GeometryKit {
    static func rectangleArea(width: Int, height: Int) -> Int {
        return width * height
    }
}

let width = 8
let height = 3
let area = GeometryKit.rectangleArea(width: width, height: height)
let label = "area=\(area)"

print(label)

enum GeometryKit {
    static func rectangleArea(width: Int, height: Int) -> Int {
        return width * height
    }
}

let width = 5
let height = 3
let area = GeometryKit.rectangleArea(width: width, height: height)
let label = "area=\(area)"

print(label)

enum GeometryKit {
    static func rectangleArea(width: Int, height: Int) -> Int {
        return width * height
    }
}

let width = 12
let height = 3
let area = GeometryKit.rectangleArea(width: width, height: height)
let label = "area=\(area)"

print(label)

  1. width ← 8, height ← 3

    7let width→ 8 = 8  //@width=5, 128let height→ 3 = 39let area = GeometryKit.rectangleArea(width: width8, height: height3)10let label = "area=\(area)"

  2. static func rectangleArea(width: Int, height: Int) -> Int

    1enum GeometryKit {2    static func rectangleArea(width8: Int, height3: Int) -> Int {3        return width8 * height34    }

  3. area ← 24, label ← area=24

    8let height = 39let area→ 24 = GeometryKit.rectangleArea(width: width8, height: height3)10let label→ area=24 = "area=\(area24)"1112print(labelarea=24)
    outputarea=24

  1. width ← 5, height ← 3

    7let width→ 5 = 58let height→ 3 = 39let area = GeometryKit.rectangleArea(width: width5, height: height3)10let label = "area=\(area)"

  2. static func rectangleArea(width: Int, height: Int) -> Int

    1enum GeometryKit {2    static func rectangleArea(width5: Int, height3: Int) -> Int {3        return width5 * height34    }

  3. area ← 15, label ← area=15

    8let height = 39let area→ 15 = GeometryKit.rectangleArea(width: width5, height: height3)10let label→ area=15 = "area=\(area15)"1112print(labelarea=15)
    outputarea=15

  1. width ← 12, height ← 3

    7let width→ 12 = 128let height→ 3 = 39let area = GeometryKit.rectangleArea(width: width12, height: height3)10let label = "area=\(area)"

  2. static func rectangleArea(width: Int, height: Int) -> Int

    1enum GeometryKit {2    static func rectangleArea(width12: Int, height3: Int) -> Int {3        return width12 * height34    }

  3. area ← 36, label ← area=36

    8let height = 39let area→ 36 = GeometryKit.rectangleArea(width: width12, height: height3)10let label→ area=36 = "area=\(area36)"1112print(labelarea=36)
    outputarea=36
namespace Swift modules are namespaces, and small programs can also group related static helpers under an enum or struct name.