Strutter

strutter.swift

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

import UIKit

infix operator |=| { associativity left }
infix operator |=>| { associativity left }
infix operator |=<| { associativity left }

private func _install(constraint: NSLayoutConstraint) {
    // Only disable AutoresizineMask on left item, secondItem may need it enabled
    if let v1 = constraint.firstItem as? UIView where v1.superview != nil {
        v1.translatesAutoresizingMaskIntoConstraints = false
    }
    constraint.active = true
}

func |=|<T: NSLayoutAnchor>(leftAnchor: T, pair: (NSLayoutAnchor, CGFloat)) -> T {
    _install(leftAnchor.constraintEqualToAnchor(pair.0, constant: pair.1))
    return leftAnchor
}

func |=|<T: NSLayoutAnchor>(leftAnchor: T, rightAnchor: NSLayoutAnchor) -> T {
    leftAnchor |=| (rightAnchor, 0)
    return leftAnchor
}

func |=>|<T: NSLayoutAnchor>(leftAnchor: T, rightAnchor: NSLayoutAnchor) -> T {
    leftAnchor |=>| (rightAnchor, 0)
    return leftAnchor
}

func |=>|<T: NSLayoutAnchor>(leftAnchor: T, pair: (NSLayoutAnchor, CGFloat)) -> T {
    _install(leftAnchor.constraintGreaterThanOrEqualToAnchor(pair.0, constant: pair.1))
    return leftAnchor
}

func |=<|<T: NSLayoutAnchor>(leftAnchor: T, rightAnchor: NSLayoutAnchor) -> T {
    leftAnchor |=<| (rightAnchor, 0)
    return leftAnchor
}

func |=<|<T: NSLayoutAnchor>(leftAnchor: T, params: (rightAnchor: NSLayoutAnchor, constant: CGFloat)) -> T {
    _install(leftAnchor.constraintLessThanOrEqualToAnchor(params.0, constant: params.1))
    return leftAnchor
}

func |=|<T: NSLayoutDimension>(leftAnchor: T, constant: CGFloat) -> T {
    _install(leftAnchor.constraintEqualToConstant(constant))
    return leftAnchor
}

func |=|<T: NSLayoutDimension>(leftAnchor: T, rest: (NSLayoutDimension, CGFloat, CGFloat)) -> T {
    _install(leftAnchor.constraintEqualToAnchor(rest.0, multiplier: rest.1, constant: rest.2))
    return leftAnchor
}

func |=|<T: NSLayoutDimension>(leftAnchor: T, rest: (NSLayoutDimension, CGFloat)) -> T {
    leftAnchor |=| (rest.0, rest.1, 1)
    return leftAnchor
}


let v = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 140))
let subv = UIView()
v.backgroundColor = UIColor.whiteColor()
subv.backgroundColor = UIColor.blueColor()
v.addSubview(subv)

subv.widthAnchor |=| 20
subv.heightAnchor |=| 30
subv.centerXAnchor |=| v.centerXAnchor
subv.topAnchor |=| (v.topAnchor, 10)

let subv2 = UIView()
subv2.backgroundColor = UIColor.greenColor()
v.addSubview(subv2)

let subv3 = UIView()
subv3.backgroundColor = UIColor.orangeColor()
v.addSubview(subv3)

subv2.widthAnchor |=| subv3.widthAnchor |=| subv.widthAnchor
subv2.heightAnchor |=| subv3.heightAnchor |=| subv.heightAnchor
subv2.leftAnchor |=| subv3.leftAnchor |=| subv.leftAnchor

subv2.topAnchor |=| (subv.bottomAnchor, 10)
subv3.topAnchor |=| (subv2.bottomAnchor, 10)

v.layoutIfNeeded()
v