What’s new in Foundation Notes

3 min readJun 23, 2021

AttributedString

New AttributedString type

Swift Value type
same character-counting behavior as Swift String
Localizable
Safety and security in mind

Example:

var thanks = AttributedString("Thank you!")
thanks.font = .body.bold()var website = AttributedString("Please visit our website.")
website.font = .body.italic()
website.link = URL(string: "http://www.example.com")// AttributeContainer - a place you can hold attributes and values on their own without the string
var container = AttributeContainer()
container.foregroundColor = .red
container.underlineColor = .primarythanks.mergeAttributes(container)
website.mergeAttributes(container)

AttributedString views: give us insight of the attribute string, they're Swift collections

characters - which provides access to the String instance
runs - which provides access to the attributes

var message = AttributedString(localized: "...") 
let characterView = message.characters 
for i in characterView.indices where characterView[i].isPunctuation { 
  message[i..<characterView.index(after: i)].foregroundColor = .orange
}let runCount= message.runcs.count
var insecureLinks: [URL] = []
for (value, range) in message.runs[\.link] {
   if let v = value, v.scheme != "https" {
      insecureLinks.append(v)
   }
}

Localization

both AttributedString and NSAttributedString are fully localizable
in Swift, we can now use string interpolation, like in SwiftUI

String(localized: "Would you like to save the document “\(document)”?")
AttributedString(localized: "Would you like to save the document “\(document)”?")

Xcode can generate your strings files from these new initializers using the compiler: Turn this on by going to your build settings, look for the localization settings, and turn on Use Compiler to Extract Swift Strings

Markdown

AttributedString comes with markdown support, including links and custom attributes:

This text contains [a link](http://www.example.com).This text contains ![an image](http://www.example.com/my_image.gif).This text contains ^[a custom attribute](rainbow: 'extreme').

Here’s an example of custom attribute and how to parse it:

// Attribute scopes 
extension AttributeScopes 
  struct CaffeAppAttributes: AttributeScope {
    let rainbow: RainbowAttribute 
    let swiftUI: SwiftUIAttributes 
  }
  var caffeApp: CaffeAppAttributes.Type { CaffeAppAttributes.self } 
}let header = AttributedString(
  localized: "^[Fast & Delicious](rainbow: 'extreme') Food",
  including: \.caffeApp
)

Formatters

bran new API
no need to cache formatter anymore

Date formatter example:

func formattingDates() {
  // Note: This will use your current date & time plus current locale. 
  // Example output is for en_US locale.
  let date = Date.now  let formatted = date.formatted() // equivalent to date.formatted(.dateTime) 
  // example: "6/7/2021, 9:42 AM"
  print(formatted)  let onlyYearDayMonth = date.formatted(.dateTime.year().day().month())
  // example: "Jun 7, 2021"
  print(onlyYearDayMonth)  let onlyYearDayMonthWide = date.formatted(.dateTime.year().day().month(.wide))
  // example: "June 7, 2021"
  print(onlyYearDayMonthWide)  let onlyDate = date.formatted(date: .numeric, time: .omitted)
  // example: "6/7/2021"
  print(onlyDate)  let onlyTime = date.formatted(date: .omitted, time: .shortened)
  // example: "9:42 AM"
  print(onlyTime)
}

all these formatted(date:) parameters are called fields
fields order do not matter
all fields have a default for the shortest versions of the API

Automatic Grammar Agreement

Makes localization easy when a certain sentence need to change based on the quantity and gender of the objects, we only need to provide the singular word, Foundation will take care of plurals and more.