zhihuitang

Python3 Virtualenv Setup

Requirements

• Python 3
• Pip 3

$ brew install python3

zhihuitang

struct Identifier: Hashable {
    let string: String
}

extension Identifier: ExpressibleByStringLiteral {
    init(stringLiteral value: String) {
        string = value
    }
}

zhihuitang

class Observable<Value> {
    private var value: Value
    private var observations = [UUID : (Value) -> Void]()

    init(value: Value) {
        self.value = value
    }

    func update(with value: Value) {
        self.value = value

zhihuitang

import UIKit
import CoreGraphics

extension UIView {
  func createRoundedRectPath(for rect: CGRect, radius: CGFloat) -> CGMutablePath {
    let path = CGMutablePath()
    
    let midTopPoint = CGPoint(x: rect.midX, y: rect.minY)
    path.move(to: midTopPoint)
    

zhihuitang

/// Copyright (c) 2019 Razeware LLC
///
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
///
/// The above copyright notice and this permission notice shall be included in

zhihuitang

extension Optional where Wrapped: Collection {
    var isNilOrEmpty: Bool {
        return self?.isEmpty ?? true
    }
}

zhihuitang

import QuartzCore

public extension CGRect {
  public init(centre: CGPoint, size: CGSize) {
    self.init(origin: centre.applying(CGAffineTransform(translationX: size.width / -2, y: size.height / -2)), size: size)
  }
  
  public var centre: CGPoint {
    return CGPoint(x: midX, y: midY)
  }

zhihuitang

public extension CGSize {
  public func rescale(_ scale: CGFloat) -> CGSize {
    return applying(CGAffineTransform(scaleX: scale, y: scale))
  }
}

zhihuitang

public extension Collection {

    /// Returns the element at the specified index if it is within bounds, otherwise nil.
    subscript (safe index: Index) -> Element? {
        return indices.contains(index) ? self[index] : nil
    }
}

zhihuitang

import Foundation

/// An abstract class that makes building simple asynchronous operations easy.
/// Subclasses must implement `execute()` to perform any work and call
/// `finish()` when they are done. All `NSOperation` work will be handled
/// automatically.
open class AsynchronousOperation: Operation {

    // MARK: - Properties