keehun

// ...
label.adjustsFontForContentSizeCategory = true

NotificationCenter.default.addObserver(self,
                                       selector: #selector (uiContentSizeCategoryChanged),
                                       name: .FontMetricsContentSizeCategoryDidChange,
                                       object: nil)
// ...
// ...

keehun

import Foundation
import UIKit

// MARK: - AttributedStringView
class AttributedStringView: UIView {

    /// `FontSetter` is a closure type used to recalculate the font size.
    typealias FontSetter = () -> UIFont

    /// A `UILabel` that will render the attributed string with Dynamic Type.

keehun

extension NSCharacterSet {

    var characters: [String] {
        /// An array to hold all the found characters
        var characters: [String] = []

        /// Iterate over the 17 Unicode planes (0..16)
        for plane:UInt8 in 0..<17 {
            /// Iterating over all potential code points of each plane could be expensive as
            /// there can be as many as 2^16 code points per plane. Therefore, only search

keehun

let string4 = "᧐᪂᧐"
print("\"\(string4)\" only contains numbers: \(isValidNumeral(input4: string4))")
/// "᧐᪂᧐" only contains numbers: true

keehun

func isValidNumeral(input4: String) -> Bool {
    let numbers = CharacterSet.decimalDigits
    let rangeOfInvalidCharacters = input4.rangeOfCharacter(from: numbers.inverted)
    return rangeOfInvalidCharacters == nil
}

let string1 = "qwerty12345"
let string2 = "qwerty"
let string3 = "12345"

keehun

let numbers: NSCharacterSet = NSCharacterSet.decimalDigits as NSCharacterSet
let character: UTF32Char = UTF32Char(48) /// U+0030 is "0" (48 Decimal = 0x30 Hex)
numbers.longCharacterIsMember(character) /// returns `true`

keehun

print(CharacterSet.decimalDigits)
/// <CFCharacterSet Predefined DecimalDigit Set>

keehun

let stringToCheck: String = "42"
let numbers: CharacterSet = CharacterSet.decimalDigits
let stringIsANumber: Bool = stringToCheck.rangeOfCharacter(from: numbers.inverted) == nil
/// returns: `true`

keehun

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keehun

import XCTest
@testable import PracticalDynamicTypePart2

class PracticalDynamicTypePart2Tests: XCTestCase {

    var subject: Hal9000!

    override func setUp() {
        super.setUp()
        subject = Hal9000()