A simple question, but I am not able to find the answer myself. Note - I tried ProcessInfo.environment but it does not include system env vars.

I am trying to encode/decode JSON data, and I have the following code: struct SomeOrdinaryClass: Decodable { // ... } struct SomeBox<T>: Decodable { var data: T? } But Xcode gives me the following error: myfile.swift:16:8 Type 'SomeBox' does not conform to protocol 'Decodable' Is there anyway to overcome this?

I have a need to wrap several kinds of objects into a dictionary say [String: Any?], but how do I tell that the Any? object is all Encodable? let params: [String: Any?] = ["num": 123, "text": "abc", "obj": encodableobject] JSONEncoder().encode(params) // compiler error because Any? is not Encodable

The following code compiles fine in a normal Swift app, but not in the accompanying unit test bundle. I don't have any idea why. import Foundation struct Dummy: NSObject { // Error: Inheritance from non-protocol type 'NSObject' var name: String? }

This may sound strange, but I encounter real world need on this. private var queryItems_: [URLQueryItem]? private var queryItems: [URLQueryItem]? { get { if queryItems_ == nil { if !queries.isEmpty { queryItems_ = queries.map { (key: String, value: String?) in return URLQueryItem(name: key, value: value) } } } return queryItems_ } } /// Query strings public private(set) lazy var queries = [String: String?]() { didSet { queryItems_ = nil } } The queryItems will be (re)created on get if queries property was changed. What I wish is that I could use queryItems as a simple var property but let me do my logic in its getter. Is this supported already?

I want to expand the first only root node when NSOutlineView is finished loading all data. How to get notified in code (possibly by some delegate function)?

In many cases, I need to get the value from a dictionary given a key (usually a string). I have the following helper class: public class ObjectCache<T> { private var cache = [String: T]() subscript(name: String) -> T? { get { return cache[name] } set { cache[name] = newValue } } func get(_ name: String, with builder: () -> T?) -> T? { var obj = cache[name] if obj == nil { obj = builder() cache[name] = obj } return obj } } This saves much keyboard typing and avoid common errors of oversight. Like below: let serviceURL = self.urlCache.get(name) { return comp.url }! Now my question is - Does Swift provide some builtin functionality like this? I just hope I did not re-event the wheel.

I came across an article about extension of Optional (https://useyourloaf.com/blog/empty-strings-in-swift/), but I cannot get it to work for the Optional extension. extension Optional where Wrapped == String { var isBlank: Bool { return self?.isBlank ?? true } } func testIsBlank() { for s in [nil, "", " ", "\t", "abc"] { print(s?.isBlank) } } For nil value, the output is still nil. I see the article is quite old dated back in 2019. There must be some changes in the language specs. What's going on here?

I have a test app. I added some extension classes to one of source code like below: extension String { func addPathComponent(_ path: String) -> String { return (self as NSString).appendingPathComponent(path) } func sameText(with: String) -> Bool { return self.caseInsensitiveCompare(with) == .orderedSame } var isBlank: Bool { allSatisfy { $0.isWhitespace } } } extension Optional where Wrapped == String { var isBlank: Bool { self?.isBlank ?? true } } Now the symbol navigator is polluted with many system classes: BTW, I am using Xcode 14.3.1.

I am working on an app which I plan to submit to App Store in 2 weeks. Now I have a headache with Array type. I have the following API design in my app: class SomeParser { func getTranslations(_ locale: String) -> [TranslationUnit]? { // Check if the locale units are already in a cache, if not build a new list // and return the list } } class MainVC { func doTranslation() { var list = parser.getTranslation("en") // Modify some units in the list. // How to put it back to cache? } } Now the problem is that since Array is a value type, the modified list is isolated. The only way to reflect the changes into cache is put the modified list back to cache: translationCache[locale] = modifiedList But this is counter-intuitive and waste of performance. Is there anyway to workaround this problem?

I have the following class: /// Act as a reference container for value types. public class ValueBox<ValueType: ??> { public var value: ValueType public init() { value = ValueType() // Compiler error } public init(_ value: ValueType) { self.value = value } } Is it possible to specify the generic type ValueType can be inited?

I have a weird problem with HTTPS connection. Task <A19A5441-F5CD-4F8C-8C88-73FC679D8AE0>.<1> finished with error [-1200] Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." I am trying to bypass server certificate of my website because it's self-signed. The following code works in a test app, but not in another app. They have exactly have the same entitlements: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.files.user-selected.read-write</key> <true/> <key>com.apple.security.network.client</key> <true/> </dict> </plist> func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) { let protectionSpace = challenge.protectionSpace guard protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust, protectionSpace.host.contains("mywebsite.net") else { completionHandler(.performDefaultHandling, nil) return } guard let serverTrust = protectionSpace.serverTrust else { completionHandler(.performDefaultHandling, nil) return } let credential = URLCredential(trust: serverTrust) completionHandler(.useCredential, credential) } @IBAction func testMenuItem_select(_ sender: Any) { print("\(sender)") Preferences.instance.openTipShowed = false testURLSession() func testURLSession() { let session = URLSession(configuration: URLSessionConfiguration.ephemeral, delegate: self, delegateQueue: nil) let url2 = "https://www.mywebsite.net/spiders.txt" let url3 = "https://www.apple.com/" let url = URL(string: url2)! var request = URLRequest(url: url) let task = session.dataTask(with: request) { data, response, error in if let error { print(error) } if let data { let text = String(data: data, encoding: .utf8) print("HTTP response object:", response ?? "") print("HTTP resonse text:", text ?? "<empty response>") } } task.resume() } }

I have the following code: let file = "/path/to/en.lproj/Localizable.strings" let dec = PropertyListDecoder() var f: PropertyListSerialization.PropertyListFormat = .openStep do { //let data = strings.data(using: .utf8)! let data = try Data(contentsOf: URL(fileURLWithPath: file)) let list = try dec.decode([String: String].self, from: data, format: &f) print("foramt:", f.rawValue) list.forEach { print($0.key, $0.value) } } catch { print(error) } It seems PropertyListDecoder can correctly decode .strings file format; detected format is openStep (value is 1). But I am note sure because I couldn't find any docs on PropertyListDecoder about .strings file. Can anyone confirm this?

// The builtin encoding does not support GBK/GB2312 String(data: data, encoding: .GBK) How do I convert data which is encoded in GBK/GB2312 (or anything else) to a string instance?

I cannot get any clue on the differences between these 2 functions of Array type. Can anyone explain by examples?