Embed Directive in Swift

Here’s the translation of the Go embed directive example to Swift:

Our first program demonstrates how to embed files and folders into the Swift binary at build time. Swift doesn’t have a direct equivalent to Go’s embed directive, but we can achieve similar functionality using Swift’s bundle resources.

import Foundation

// In Swift, we use the Bundle class to access resources
// that are embedded in the app bundle.

// Read the contents of a single file
let fileString = Bundle.main.stringFromResource("single_file", ofType: "txt")
print(fileString ?? "Failed to load single_file.txt")

// Read the contents of a file as Data
if let fileData = Bundle.main.dataFromResource("single_file", ofType: "txt") {
    print(String(data: fileData, encoding: .utf8) ?? "Failed to convert data to string")
}

// Read multiple files from a folder
let fileManager = FileManager.default
let bundleURL = Bundle.main.bundleURL.appendingPathComponent("folder")

do {
    let fileURLs = try fileManager.contentsOfDirectory(at: bundleURL, includingPropertiesForKeys: nil)
    
    for fileURL in fileURLs where fileURL.pathExtension == "hash" {
        if let content = try? String(contentsOf: fileURL) {
            print(content)
        }
    }
} catch {
    print("Error reading directory: \(error)")
}

To use this code, you need to add the files to your Xcode project and ensure they are included in the target’s “Copy Bundle Resources” build phase.

1. Create a folder named “folder” in your project directory.

2. Add the following files to the “folder”:

   • single_file.txt (containing “hello swift”)
   • file1.hash (containing “123”)
   • file2.hash (containing “456”)

3. In Xcode, right-click on your project in the navigator and choose “Add Files to [YourProject]”.

4. Select the “folder” directory and make sure “Create folder references” is selected.

5. Ensure the files are added to your target’s “Copy Bundle Resources” build phase.

When you run the program, it should output:

hello swift
hello swift
123
456

Note that Swift’s approach to embedding resources is different from Go’s. In Swift, resources are typically bundled with the application at build time and accessed at runtime using the Bundle class. This provides a similar end result to Go’s embed directive, allowing you to include arbitrary files in your binary and access them at runtime.