Standard extensions for Foundation framework
-
RawCodingKey allows you to create CodingKeys from literals
-
Extensions for encoder and decoder allow you to create an object with a contextual container
-
Extensions for coding containers automatically infer type from context
init(from decoder: Decoder) throws {
self = try container.decode(RawCodingKey.self) { container in
return .init(
someProperty1: container.decode("someProperty1"),
someProperty2: container.decode("some_property_2")
)
}
}
func encode(to encoder: encoder) throws {
try encoder.encode(RawCodingKey.self) { container in
try container.encode(someProperty1, forKey: "someProperty1")
try container.encode(someProperty2, forKey: "some_property_2")
}
}
store(_:in:)
- stores value in some variable in locked contextmutate(_:with:)
- passes given object to locked contextassign(_:to:on:)
- stores value in object property in locked contextexecute(_:)
- provides new locked context
orThrow(_:)
- unwraps an optional or throws specified errorisNil
/isNotNil
/isNilOrEmpty
or()
- coalesing aliasunwrap()
- returns unwrapping Resultassign(to:on:)
- assigns wrapped value to a specified target property by the keyPathifLetAssign(to:on:)
- assigns wrapped value to a specified target property by the keyPath if an optional was not nil
struct State {
var value: Int = 0
}
@Resettable
let state = State()
state.value = 1 // value == 1
state.value *= 10 // value == 10
state.undo() // value == 1
state.value += 1 // value == 2
state.undo() // value == 1
state.redo() // value == 2
CoW container, which allows you to recursively include single instances of value types
struct ListNode<Value> {
var value: Value
@Indirect
var next: ListNode<Value>?
}
class MyView: UIView {
private let label: UILabel
@PropertyProxy(\MyView.label.text)
var text: String?
}
let view: MyView = .init()
view.label.text // ❌
view.text = "Hello, World!"
Basic helpers for object association are available in a base package
extension UIViewController {
var someStoredProperty: Int {
get { getAssociatedObject(forKey: #function).or(0) }
set { setAssociatedObject(newValue, forKey: #function) }
}
}
let value: Bool = getAssociatedObject(forKey: "value", from: object)
But the full power of associated objects is provided by FoundationExtensionsMacros
target
By default
@AssociatedObject
macro uses.retain(.nonatomic)
for classes and.copy(.nonatomic)
objc_AssociationPolicy
for structs.
import FoundationExtensionsMacros
extension SomeClass {
@AssociatedObject
var storedVariableInExtension: Int = 0
@AssociatedObject(readonly: true)
var storedVariableInExtension: SomeObject = .init()
@AssociatedObject
var optionalValue: Int?
@AssociatedObject
var object: Int?
@AssociatedObject(threadSafety: .atomic)
var threadSafeValue: Int?
@AssociatedObject(threadSafety: .atomic)
var threadSafeObject: Object?
@AssociatedObject(policy: .assign)
var customPolicyValue: Int?
@AssociatedObject(policy: .retain(.atomic))
var customPolicyThreadSafeObject: Object?
}
Macros require swift-syntax compilation, so it will affect cold compilation time
This package also provides some sugar for objc method swizzling
extension UIViewController {
// Runs once in app lifetime
// Repeated calls do nothing
private static let swizzle: Void = {
// This example is not really representative since these methods
// can be simply globally overriden, but it's just an example
// for the readme and you can find live example at
// https://github.com/capturecontext/combine-cocoa-navigation
objc_exchangeImplementations(
#selector(viewWillAppear)
#selector(__swizzledViewWillAppear)
)
objc_exchangeImplementations(
#selector(viewDidAppear)
#selector(__swizzledViewDidAppear)
)
}()
@objc dynamic
private func __swizzledViewWillAppear(_ animated: Bool) {
__swizzledViewWillAppear(animated) // calls original method
print(type(of: self), ObjectIdentifier(self), "will appear")
}
@objc dynamic
private func __swizzledViewDidAppear(_ animated: Bool) {
__swizzledViewDidAppear(animated) // calls original method
print(type(of: self), ObjectIdentifier(self), "did appear")
}
}
You can add FoundationExtensions 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/capturecontext/swift-foundation-extensions.git"
into the package repository URL text field - Choose products you need to link them to your project.
If you use SwiftPM for your project, you can add StandardExtensions to your package file.
.package(
url: "https://github.com/capturecontext/swift-foundation-extensions.git",
.upToNextMinor(from: "0.5.0")
)
Do not forget about target dependencies:
.product(
name: "FoundationExtensions",
package: "swift-foundation-extensions"
)
.product(
name: "FoundationExtensionsMacros",
package: "swift-foundation-extensions"
)
This library is released under the MIT license. See LICENCE for details.