FunctionalViewStyleExperiments2

FunctionalViewStyleExperiments2.swift

//: Playground - noun: a place where people can play

import UIKit

import UIKit
import XCPlayground
import PlaygroundSupport


let viewController = UIViewController()
viewController.view.backgroundColor = .white

let view = UIView()
view.backgroundColor = .orange

view.frame = CGRect(x: 100, y: 100, width: 100, height: 100)
viewController.view.addSubview(view)

PlaygroundPage.current.liveView = viewController

struct Style {
    typealias Apply = (UIView) -> UIView
    let apply: Apply
    
    init() {
        apply = { view in
            return view
        }
    }
    
    init(apply: @escaping Apply) {
        self.apply = apply
    }
}

extension Style {
    
    func compose(
        apply apply1: @escaping Apply,
        with apply2: @escaping Apply
        ) -> Apply {
        return { view in
            return apply2(apply1(view))
        }
    }
    
    func newApplyAdded(_ newApply: @escaping Apply) -> Style {
        return Style(apply: compose(apply: apply, with: newApply))
    }
    
    func cornerRadius(_ radius: CGFloat) -> Style {
        let cornerRadiusApply: Apply = { view in
            view.layer.cornerRadius = radius
            return view
        }
        return newApplyAdded(cornerRadiusApply)
    }
    
    func borderWidth(_ width: CGFloat) -> Style {
        let borderWidthApply: Apply = { view in
            view.layer.borderWidth = width
            return view
        }
        return newApplyAdded(borderWidthApply)
    }
    
    func borderColor(_ color: CGColor) -> Style {
        let borderColorApply: Apply = { view in
            view.layer.borderColor = color
            return view
        }
        return newApplyAdded(borderColorApply)
    }
}

let finalStyle = Style()
    .borderWidth(10.0)
    .cornerRadius(10.0)
    .borderColor(UIColor.blue.cgColor)
    
finalStyle
    .apply(view)