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View TrendsViewModel.m
// PFTrendsViewModel.m
// SUM
// Created by Ben Guo on 11/26/14.
// Copyright (c) 2014 Project Florida. All rights reserved.
#import "PFTestUtilities.h"
#import "PFTrendsViewModel.h"
View address.swift
// before
func formattedAddress() -> String {
let lines:NSMutableArray = NSMutableArray(capacity: 4)
let zipStateCityArgs:NSMutableArray = NSMutableArray(capacity: 3)
let zip = self.stringValueForKeyPath("address_zip")
let city = self.stringValueForKeyPath("address_city")
let state = self.stringValueForKeyPath("address_state")
for arg in [zip, city, state] {
View enumFrom.swift
protocol StringDecodable {
init?(string: String)
extension Dictionary where Key: JSONKey, Value: AnyObject {
/// Converts a string to an enum value
func enumFrom<T: StringDecodable>(key: Key, _ enumType: T.Type) -> T? {
if let s = self[key] as? String {
return enumType.init(string: s)
View currenttype.swift
import Cocoa
protocol Pet {
var name : String { get }
func renamed(newName: String) -> Self
struct Fish : Pet {
let name : String
func renamed(newName: String) -> Fish {
benzguo / Spotify.xml
Created Apr 10, 2015
View Spotify.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dictionary SYSTEM "file://localhost/System/Library/DTDs/sdef.dtd">
<dictionary title="Dictionary">
<suite name="Spotify Suite" code="spfy" description="Spotify specific classes.">
<enumeration name="ePlS" code="ePlS">
<enumerator name="stopped" code="kPSS">
<cocoa integer-value="0"/>
<enumerator name="playing" code="kPSP">
<cocoa integer-value="1"/>

Common Save Patterns

Standard background save

Assuming that you don't care which NSManagedObjectContext is used, and you just want to make some changes and save them in the background, use the following method. 90% of the time, this is what you'll want.

NSManagedObjectSubclass *myObject = [NSManagedObjectSubclass MR_findFirst];

[MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext) {
benzguo / Localization.swift
Last active Aug 29, 2015
Localize all the strings!
View Localization.swift
import Foundation
infix operator | {}
func | (lhs: String, rhs: String) -> String {
return NSLocalizedString(lhs, comment: rhs)
postfix operator | {}
postfix func | (s: String) -> String {
return NSLocalizedString(s, comment: "")

Integrating Swift With Objective-C


  • Swift is modern, type-safe, expressive, performant

  • but Objective-C remains a first-class citizen

  • Same design patterns, Cocoa APIs

  • "We do not want you to rewrite or stop improving your existing code!"

  • Should you use unowned or weak for delegates?

  • To expose Objective-C to Swift, use a bridging header


WWDC 2014

Extending Swift

Making something anonymous

for (key, _) in dictionary {
benzguo /
Created Jun 6, 2014

Intro To LLDB and the Swift REPL

Sean Callanan

Basic debugging

  • lldb commands
    • ti/ thread info
      • EXC_BAD_INSTRUCTION = CPU doesn't understand an instruction
        • typically used in assertions -> Assertion failure
    • bt / thread backtrace
      • prints all frames on the stack of the current thread
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