Swift Declarative Configuration
Swift Declarative Configuration (SDC, for short) is a tiny library, that enables you to configure your objects in a declarative, consistent and understandable way, with ergonomics in mind. It can be used to configure any objects on any platform, including server-side-swift.
Products
-
Provides modification functions for copying and modifying immutable stuff. It is useful for self-configuring objects like builder, when modificating methods should return modified
self -
KeyPath functional wrappers, one is generalized and the other is for enums. CasePath is a dependency.
-
Funtional configurator for anything, enables you to specify modification of an object and to apply the modification later.
Also contains self-implementing protocols (
ConfigInitializable,CustomConfigurable) to enable you add custom configuration support for your types (NSObjectalready conforms to it for you). -
Functional builder for anything, enables you to modify object instances in a declarative way. Also contains
BuilderProviderprotocol with a computedbuilderproperty and implements that protocol onNSObjecttype. -
Functional closures allow you to setup functional handlers & datasources, the API may seem a bit strange at the first look, so feel free to ask or discuss anything here.
-
Wraps and exports all the products.
Basic Usage
See tests for more
No SDC
class ImageViewController: UIViewController {
let imageView = UIImageView()
override func loadView() {
self.view = imageView
}
override func viewDidLoad() {
super.viewDidLoad()
imageView.contentMode = .scaleAspectFit
imageView.backgroundColor = .black
imageView.layer.masksToBounds = true
imageView.layer.cornerRadius = 10
}
}FunctionalConfigurator
import FunctionalConfigurator
class ImageViewController: UIViewController {
let imageView = UIImageView { $0
.contentMode(.scaleAspectFit)
.backgroundColor(.black)
.layer.masksToBounds(true)
.layer.cornerRadius(10)
}
override func loadView() {
self.view = imageView
}
}Note: This way is recommended, but remember, that custom types MUST implement initializer with no parameters even if the superclass already has it or you will get a crash otherwise.
FunctionalBuilder
import FunctionalBuilder
class ImageViewController: UIViewController {
let imageView = UIImageView().builder
.contentMode(.scaleAspectFit)
.backgroundColor(.black)
.layer.masksToBounds(true)
.layer.cornerRadius(10)
.build()
override func loadView() {
self.view = imageView
}
}Note: This way is recommended too, and it is more safe, because it modifies existing objects.
FunctionalClosures
No SDC
Declaration
public class TapGestureRecognizer: UITapGestureRecognizer {
var onTapGesture: ((TapGestureRecognizer) -> Void)?
init() {
super.init(target: nil, action: nil)
commonInit()
}
override public init(target: Any?, action: Selector?) {
super.init(target: target, action: action)
commonInit()
}
private func commonInit() {
self.addTarget(self, action: #selector(handleTap))
}
@objc private func handleTap(_ recognizer: TapGestureRecognizer) {
onTapGesture?(recognizer)
}
}Usage
let tapRecognizer = TapGestureRecognizer()
// handler setup
tapRecognizer.onTapGesture = { recognizer in
// ...
}
// call from the outside
tapRecognizer.onTapGesture?(tapRecognizer)With SDC
Declaration
public class TapGestureRecognizer: UITapGestureRecognizer {
@Handler<TapGestureRecognizer>
var onTapGesture
init() {
super.init(target: nil, action: nil)
commonInit()
}
override public init(target: Any?, action: Selector?) {
super.init(target: target, action: action)
commonInit()
}
private func commonInit() {
self.addTarget(self, action: #selector(handleTap))
}
@objc private func handleTap(_ recognizer: TapGestureRecognizer) {
_onTapGesture(recognizer)
}
}Usage
let tapRecognizer = TapGestureRecognizer()
// handler setup now called as function
tapRecognizer.onTapGesture { recognizer in
// ...
}
// call from the outside now uses propertyWrapper projectedValue API, which is not as straitforward
// and it is nice, because:
// - handlers usually should not be called from the outside
// - you do not lose the ability to call it, but an API tells you that it's kinda private
tapRecognizer.$onTapGesture?(tapRecognizer)Also you can create such an instance with Configurator:
let tapRecognizer = TapGestureRecognizer { $0
.$onTapGesture { recognizer in
// ...
}
}More
Builder
Customize any object by passing initial value to a builder
let object = Builder(Object())
.property.subproperty(value)
.build() // Returns modified objectFor classes you can avoid returning a value by calling apply method, instead of build
let _class = _Class()
Builder(_class)
.property.subproperty(value)
.apply() // Returns VoidConform your own types to BuilderProvider protocol to access builder property.
import CoreLocation
import DeclarativeConfiguration
extension CLLocationCoordinate2D: BuilderProvider {}
// Now you can access `location.builder.latitude(0).build()`Configurator
Note: Your NSObject classes must implement
init()to use Configurators. It's a little trade-off for the convenience it brings to your codebase, see tests for an example.
DataSource
OptiomalDataSource and DataSource types are very similar to the Handler, but if Handler<Input> is kinda OptionalDataSource<Input, Void>, the second one may have different types of an output. Usage is similar, different types are provided just for better semantics.
Installation
Basic
You can add DeclarativeConfiguration to an Xcode project by adding it as a package dependency.
- From the File menu, select Swift Packages › Add Package Dependency…
- Enter
"https://github.com/makeupstudio/swift-declarative-configuration"into the package repository URL text field - Choose products you need to link them to your project.
Recommended
If you use SwiftPM for your project, you can add DeclarativeConfiguration to your package file. Also my advice will be to use SSH.
.package(url: "git@github.com:makeupstudio/swift-declarative-configuration.git", .branch("main"))or
.package(url: "git@github.com:makeupstudio/swift-declarative-configuration.git", .exact("0.2.0"))Do not forget about target dependencies:
.product(
name: "DeclarativeConfiguration",
package: "swift-declarative-configuration"
)License
This library is released under the MIT license. See LICENSE for details.