Greetings,
func stepForward(_ input: Int) -> Int {
return input + 1
}
func stepBackward(_ input: Int) -> Int {
return input - 1
}
func chooseStepFunction(backward: Bool) -> (Int) -> Int {
return backward ? stepBackward : stepForward /* Error
type of expression is ambiguous without a type annotation */
}
Why am I getting this error. If I change the function to
func chooseStepFunction(backward: Bool) -> (Int) -> Int {
if backward {
return stepBackward
else {
return stepForward
}
}
Why is the previous chooseStepFunction giving me an error ?
Thx in advance
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I filed the following issue on swiftlang/swift on GitHub (Aug 8th), and a followup the swift.org forums, but not getting any replies. As we near the release of Swift 6.2, I want to know if what I'm seeing below is expected, or if it's another case where the compiler needs a fix.
protocol P1: Equatable { }
struct S1: P1 { }
// Error: Conformance of 'S1' to protocol 'P1' crosses into main actor-isolated code an can cause data races
struct S1Workaround: @MainActor P1 { } // OK
// Another potential workaround if `Equatable` conformance can be moved to the conforming type.
protocol P2 { }
struct S2: Equatable, P2 { } // OK
There was a prior compiler bug fix which addressed inhereted protocols regarding @MainActor. For Equatable, one still has to use @MainActoreven when the default actor isolation is MainActor.
Also affects Hashable and any other protocol inheriting from Equatable.
I have a simple shell script as follows:
#!/bin/bash
OUTPUT="network.$(date +'%d-%m-%y').info.txt"
SUPPORT_ID="emailaddress"
echo "---------------------------------------------------" > $OUTPUT
echo "Run date and time: $(date)" >> $OUTPUT
echo "---------------------------------------------------" >> $OUTPUT
ifconfig >> $OUTPUT
echo "---------------------------------------------------" >> $OUTPUT
echo "Network info written to file: $OUTPUT."
echo "Please email this file to: $SUPPORT_ID."
It just dumps the network config into a file. At some point I will have the file emailed out, but right now I'm just trying to figure out why the output looks like the following?
bash ./test.sh
.etwork info written to file: network.26-01-25.info.txt
.lease email this file to: emailaddress
Why in the world does the initial character of the last couple of "echo" commands get clipped and turned into periods? The echos for the output of the commands piped into the output file are fine. Strange...
Any ideas?
Topic:
Programming Languages
SubTopic:
General
Hello, I have a problem with the .onMove function. I believe I have set everything up properly. However, the moving does not seem to be working correctly. When I try to move the item, it is highlighted first, as it is supposed to be. Then, while I am moving it through the list, it disappears for some reason, and at the end of the move, it comes back to its initial place. (I use iOS 16.0 minimum, so I don't have to include the EditButton(). It works the same in the edit mode tho)
import SwiftUI
struct Animal: Identifiable {
var id = UUID()
var name: String
}
struct ListMove: View {
@State var animals = [Animal(name: "Dog"), Animal(name: "Cat"), Animal(name: "Cow"), Animal(name: "Goat"), Animal(name: "Chicken")]
var body: some View {
List {
ForEach(animals) { animal in
Text(animal.name)
}
.onMove(perform: move)
}
}
func move(from source: IndexSet, to destination: Int) {
animals.move(fromOffsets: source, toOffset: destination)
}
}
#Preview {
ListMove()
}
hi,
Is it possible to compare two vectors and get a boolean answer?
example :
uint642_t a;
uint642_t b;
.../...
if(a == b)
.../...
how to do it ?
thank
Hello,
I was expecting the code below to print the test message "line 25" because the class "API" is being called on line 57. But "line 25" is not being displayed in the debug window, please could you tell me why?
This is the debugging window:
line 93
0
line 93
0
line 93
0
import UIKit
// not sure these 2 below are needed
import SwiftUI
import Combine
struct NewsFeed: Codable {
var id: String
var name: String
var country: String
var type: String
var situation: String
var timestamp: String
}
let urlString = "https://www.notafunnyname.com/jsonmockup.php"
let url = URL(string: urlString)
let session = URLSession.shared
class API: ObservableObject {
let dataTask = session.dataTask(with: url!) { (data, response, error) in
print("line 25")
var dataString = String(data: data!, encoding: String.Encoding.utf8)
if error == nil && data != nil {
// Parse JSON
let decoder = JSONDecoder()
do {
var newsFeed = try decoder.decode([NewsFeed].self, from: data!)
print("line 38")
// print(newsFeed)
// print("line 125")
// print(newsFeed.count)
print(error)
}
catch{
print("Line 46, Error in JSON parsing")
print(error)
}
}
}.resume
// Make the API Call - not sure why but error clears if moved to line above
// dataTask.resume()
}
let myAPIarray = API()
class QuoteTableViewController: UITableViewController {
var newsFeed: [[String: String]] = []
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// let selectedQuote = quotes[indexPath.row]
// performSegue(withIdentifier: "moveToQuoteDetail", sender: selectedQuote)
}
override func viewDidLoad() {
super.viewDidLoad()
// tableView.dataSource = self
}
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// (viewDidLoad loads after tableView)
// #warning Incomplete implementation, return the number of rows
print("line 93")
print(newsFeed.count)
return 10
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath)
let cell = UITableViewCell ()
cell.textLabel?.text = "test"
return cell
}
/*
// Override to support conditional editing of the table view.
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
*/
/*
// Override to support editing the table view.
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
// Delete the row from the data source
tableView.deleteRows(at: [indexPath], with: .fade)
} else if editingStyle == .insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) {
}
*/
/*
// Override to support conditional rearranging of the table view.
override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the item to be re-orderable.
return true
}
*/
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destination.
// Pass the selected object to the new view controller.
// getPrice()
print("test_segue")
if let quoteViewController = segue.destination as? QuoteDetailViewController{
if let selectedQuote = sender as? String {
quoteViewController.title = selectedQuote
}
}
}
}
Topic:
Programming Languages
SubTopic:
Swift
I’m working with Swift and encountered an issue when using the contains method on an array. The following code works fine:
let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine
However, when I try to use the same contains method with the array declared in a separate constant(or variable), I get a compile-time error:
let stringArray = ["hello", "world"]
let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error
The compiler produces the following error message:
Cannot convert value of type 'Optional<String>' to expected argument type 'String'
Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine.
This confuses me because I know that Swift automatically promotes a non-optional value to an optional when comparing it with an optional value. This means "hello" should be implicitly converted to Optional("hello") for the comparison.
What I understand so far:
The contains(_:) method is defined as:
func contains(_ element: Element) -> Bool
Internally, it calls contains(where:), as seen in the Swift source code:
🔗 Reference
contains(where:) takes a closure that applies the == operator for comparison.
Since Swift allows comparing String and String? directly (String is implicitly promoted to String? when compared with an optional), I expected contains(where:) to work the same way.
My Questions:
Why does the first example work, but the second one fails with a compile-time error?
What exactly causes this error in the second case, even though both cases involve comparing an optional value with a non-optional value?
Does contains(_:) behave differently when used with an explicit array variable rather than a direct array literal? If so, why?
I know that there are different ways to resolve this, like using nil coalescing or optional binding, but what I’m really looking for is a detailed explanation of why this issue occurs at the compile-time level.
Can anyone explain the underlying reason for this behavior?
Hello
I'm using this sdk DeclaredAgeRange to get the user age range
When I'm doing in debug mode using sandbox account it is working as expected and I can get the user age range
But when I tried in TestFlight build using sandbox account it is not working and it is always return the age range 18+ and also isEligibleForAgeFeatures API is always returning false
Any advise on this?
Topic:
Programming Languages
SubTopic:
Swift
Hello everyone,
There is one thing about Objective-C's memory management that confuses me, which is a returned object's lifetime from methods with names doesn't start with "alloc", "new", "copy", or "mutableCopy".
Take this as an example, when using NSBitmapImageRep's representationUsingType:properties: method, it returns an NSData object (reference: https://developer.apple.com/documentation/appkit/nsbitmapimagerep/representation(using:properties:)?language=objc).
While testing this out, the NSData seemed to be an owned object (it doesn't get released until the end of the program).
From what I understand, this may be an auto-released object which is released at the end of an autorelease pool block.
Could someone explain this in more detail? What if I want to release that NSData object before the end of the autorelease pool block? How can I know which object is autoreleased, borrowed, or owned?
Does anyone know if there will be a Swift 6 version of "The Swift Programming Language" book and if so, when it will be released for Apple Books?
Topic:
Programming Languages
SubTopic:
Swift
I have a Swift Package that contains an Objective-C target. The target contains Objective-C literals but unfortunately the compiler says "Initializer element is not a compile-time constant", what am I doing wrong?
Based on the error triggering in the upper half, I take it that objc_array_literals is on.
My target definition looks like:
.target(
name: "MyTarget",
path: "Sources/MySourcesObjC",
publicHeadersPath: "include",
cxxSettings: [
.unsafeFlags("-fobjc-constant-literals")
]
),
I believe Objective-C literals are enabled since a long time but I still tried passing in the -fobjc-constant-literals flag and no luck.
To be clear I'm not interested in a run-time initialization, I really want it to be compile time. Does anyone know what I can do?
I've been teaching myself Objective-C and I wanted to start creating projects that don't use ARC to become better at memory management and learn how it all works. I've been attempting to build and run applications, but I'm not really sure where to start as modern iOS development is used with Swift and memory management is handled.
Is there any way to create modern applications that use Objective-C, UIKit, and not use ARC?
I have a VPN application published in the app store. Used Ikev2 for this personal VPN. There are two in-app purchases. One is 'Monthly' and another is 'Yearly' with 3 days free trial. We have seen something strange for the yearly subscriptions which has free trail, the cancellation reason through the billing issue is too high like 70-80% due to billing retry state. Some other apps which have billing issues under 10% always. We have done some research and found that if the user doesn't cancel and Apple is unable to charge then it goes to a billing retry state.
If users don't like the app, they could cancel their subscription/free trail easily but they are not doing this and why Apple unable to charge the bill after the trial ends. Am i missing something in the developer end?
At least with macOS Sequoia 15.5 and Xcode 16.3:
$ cat test.cc
#include &lt;locale.h&gt;
#include &lt;string.h&gt;
#include &lt;xlocale.h&gt;
int main(void) {
locale_t l = newlocale(LC_ALL_MASK, "el_GR.UTF-8", 0);
strxfrm_l(NULL, "ό", 0, l);
return 0;
}
$ c99 test.c &amp;&amp; ./a.out
Assertion failed: (p-&gt;val == key), function lookup_substsearch, file collate.c, line 596.
Abort trap: 6
Just read about the new @concurrent option coming to Swift 6.2 and lover it, but...
It just me, but I which these options would pick a case and stick with it...
@Sendable
@unchecked
@MainActor
@concurrent
@Observable
@ObservationIgnored
Crash Log
We have a issue with our watch app. When we do a release build with xcode 16 the watch app will not launch and crashes on watchOS 10 and below devices.
It does not do this on debug builds...and it does not do this on xcode 15 release/debug builds.
Anybody running into watch crashes on xcode 16?
Thanks
My company wants to be insure that if my Objective-C to Swift conversions fail in anyway, that the app can revert to using the older Objective-C code. By using a remotely controllable flag, the app can switch which code runs as, both are compiled into the app.
Essentially, I create a protocol that describes the original class, then both classes (with a "s" or "o" appended to them) conform to the protocol.
Protocol: Object
Objective-C class: oObject
Swift class: sObject
That said, I hit one issue that I just can't seem reason out. I create a Objective-C function that returns the appropriate class:
Class<Object> classObject(void) {
if (myFlag) {
return [sObject class];
} else {
return [oObject class];
}
}
Swift deals with this really well - I can create an initialized object using:
let object = classObject().init()
but I cannot find a way to do this in Objective-C:
Object *object = [[classSalesForceData() alloc] init];
fails with "No known class method for selector 'alloc'"
Is there a way to do this?
David
PS: my workaround is to return an allocated object:
Object *createObject(void) {
if (myFlag) {
return [sObject alloc];
} else {
return [oObject alloc];
}
}
Why Ternary operator in not called a binary Operator or ternary Operands ?
question ? answer1 : answer2
When it takes 2 operators ?
I'm trying to fix some Swift6 warnings, this one seems too strict, I'm not sure how to fix it. The variable path is a String, which should be immutable, it's a local variable and never used again inside of the function, but still Swift6 complains about it being a race condition, passing it to the task
What should I do here to fix the warning?
I have a transformation function that takes in data, executes some instructions, and returns an output. This function is dynamic and not shipped with the binary. Currently, I’m executing it using JavaScriptCore.JSContext, which works well, but the function itself is written in JavaScript.
Is there a way to achieve something similar using Swift – such as executing a dynamic Swift script, either directly or through other means? I know this is possible on macOS, but I’m not sure about iOS. I’ve also heard that extensions might open up some possibilities here. Any insights or alternative approaches would be appreciated.