Packages and Modules

Import Foundation

An import makes a module's library types and functions available to a Swift file.

Use a library after import

rawName
import_foundation.swift
Replay: real traced execution (multi-file project)
import Foundation

let rawName = "trace book"
let trimSet = CharacterSet.whitespacesAndNewlines
let normalized = rawName.trimmingCharacters(in: trimSet)
let words = normalized.split(separator: " ")
let title = words.map { word in
    word.prefix(1).uppercased() + word.dropFirst()
}.joined(separator: " ")

print(title)

import Foundation

let rawName = "swift module"
let trimSet = CharacterSet.whitespacesAndNewlines
let normalized = rawName.trimmingCharacters(in: trimSet)
let words = normalized.split(separator: " ")
let title = words.map { word in
    word.prefix(1).uppercased() + word.dropFirst()
}.joined(separator: " ")

print(title)

import Foundation

let rawName = "package guide"
let trimSet = CharacterSet.whitespacesAndNewlines
let normalized = rawName.trimmingCharacters(in: trimSet)
let words = normalized.split(separator: " ")
let title = words.map { word in
    word.prefix(1).uppercased() + word.dropFirst()
}.joined(separator: " ")

print(title)

  1. rawName ← trace book, trimSet ← <CFCharacterSet Predefined WhitespaceAndNewline Set>

    3let rawName→ trace book = "trace book"  //@rawName="swift module", "package guide"4let trimSet→ <CFCharacterSet Predefined WhitespaceAndNewline Set> = CharacterSet.whitespacesAndNewlines5let normalized→ trace book = rawNametrace book.trimmingCharacters(in: trimSet<CFCharacterSet Predefined WhitespaceAndNewline Set>)6let words→ ["trace", "book"] = normalizedtrace book.split(separator: " ")7let title→ Trace Book = words["trace", "book"].map { word in8    word.prefix(1).uppercased() + word.dropFirst()9}.joined(separator: " ")1011print(titleTrace Book)
    outputTrace Book

  1. rawName ← swift module, trimSet ← <CFCharacterSet Predefined WhitespaceAndNewline Set>

    3let rawName→ swift module = "swift module"4let trimSet→ <CFCharacterSet Predefined WhitespaceAndNewline Set> = CharacterSet.whitespacesAndNewlines5let normalized→ swift module = rawNameswift module.trimmingCharacters(in: trimSet<CFCharacterSet Predefined WhitespaceAndNewline Set>)6let words→ ["swift", "module"] = normalizedswift module.split(separator: " ")7let title→ Swift Module = words["swift", "module"].map { word in8    word.prefix(1).uppercased() + word.dropFirst()9}.joined(separator: " ")1011print(titleSwift Module)
    outputSwift Module

  1. rawName ← package guide, trimSet ← <CFCharacterSet Predefined WhitespaceAndNewline Set>

    3let rawName→ package guide = "package guide"4let trimSet→ <CFCharacterSet Predefined WhitespaceAndNewline Set> = CharacterSet.whitespacesAndNewlines5let normalized→ package guide = rawNamepackage guide.trimmingCharacters(in: trimSet<CFCharacterSet Predefined WhitespaceAndNewline Set>)6let words→ ["package", "guide"] = normalizedpackage guide.split(separator: " ")7let title→ Package Guide = words["package", "guide"].map { word in8    word.prefix(1).uppercased() + word.dropFirst()9}.joined(separator: " ")1011print(titlePackage Guide)
    outputPackage Guide
import Swift files use `import` to name the modules they depend on before using the types or helpers provided by those modules.