SLMacros

SLMacros is a Swift package that provides two macros:

• #URL("...") for creating validated Foundation.URL values from string literals.
• @CaseIdentifiable for making an enum conform to Identifiable and generating a string-based id.

Macros

#URL

#URL is a freestanding expression macro that accepts a static string literal and returns a URL.

It validates the value at compile time and emits an error when:

• the argument is not a string literal
• the string is not a valid absolute URL

Example:

import Foundation
import SLMacros

let website = #URL("https://example.com")

This works well when you want URL values to be checked during compilation instead of failing later at runtime.

@CaseIdentifiable

@CaseIdentifiable is an attached macro for enums. It:

• adds Identifiable conformance
• generates a public var id: String
• uses the enum case name as the identifier

Example:

import SLMacros

@CaseIdentifiable
enum Screen {
    case home
    case settings
    case profile(userID: Int)
}

The macro expands to behavior equivalent to:

extension Screen: Identifiable {}

extension Screen {
    public var id: String {
        switch self {
        case .home:
            "home"
        case .settings:
            "settings"
        case .profile:
            "profile"
        }
    }
}

The macro emits diagnostics when:

• it is applied to something other than an enum
• the enum has no cases
• the enum already conforms to Identifiable

Adding SLMacros To An Xcode Project

You can install SLMacros in Xcode either from GitHub or by downloading the repository and adding it as a local package.

Option 1: Install from GitHub

1. Open your app project in Xcode.
2. Choose File > Add Package Dependencies...
3. Enter the package URL:

https://github.com/StewartLynch/SLMacros

4. Choose the dependency rule you want, such as the latest version or a branch.
5. Click Add Package.
6. Add the SLMacros library product to the target that will use the macros.

Option 2: Download and add as a local package

1. Download or clone the repository from github.com/StewartLynch/SLMacros.
2. Open your app project in Xcode.
3. Choose File > Add Package Dependencies...
4. Click Add Local...
5. Select the downloaded SLMacros folder.
6. Add the SLMacros library product to the target that will use the macros.

Once the package has been added, Xcode will make the macros available to any target linked against the SLMacros product.

Importing And Using The Macros

After adding the package to your target, import the module where you want to use the macros:

import Foundation
import SLMacros

Then use them like this:

import Foundation
import SLMacros

struct Link {
    let url = #URL("https://example.com")
}

@CaseIdentifiable
enum Route {
    case home
    case profile(userID: Int)
}

Requirements

• Xcode with Swift macro support
• Swift 6 package tools as configured in Package.swift