iOS Swift Auto layout - Visual Format Language - for-loop adding multiple constraints

vfl-for-loop.swift

// Resulting code: http://cl.ly/image/0z0H2C230H3R

// the superview, `self.statsView`, just a UIView in my storyboard with a 
// trailing/leading constraint of 6, bottom/top constraint of 12 and 60pt height
var redView: UIView!
var blueView: UIView!
var yellowView: UIView!

redView = UIView()
blueView = UIView()
yellowView = UIView()

redView.setTranslatesAutoresizingMaskIntoConstraints(false)
blueView.setTranslatesAutoresizingMaskIntoConstraints(false)
yellowView.setTranslatesAutoresizingMaskIntoConstraints(false)

redView.backgroundColor = UIColor.redColor()
blueView.backgroundColor = UIColor.blueColor()
yellowView.backgroundColor = UIColor.yellowColor()

self.statsView.addSubview(redView)
self.statsView.addSubview(blueView)
self.statsView.addSubview(yellowView)

let views = [
  "red": redView,
  "blue": blueView,
  "yellow": yellowView
]

let metrics = [
  "margin": 2
]

view.addConstraints(
  NSLayoutConstraint.constraintsWithVisualFormat(
    "V:|-margin-[red(>=10)]-margin-[blue(==red)]-margin-[yellow(==red)]-margin-|",
    options: nil,
    metrics: metrics,
    views: views))

for (index, (key, val)) in enumerate(views) {
  self.statsView.addConstraints(
    NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-60-[\(key)(>=100)]-60-|", options: nil, metrics: nil, views: views))
}

// Or preferrably omit unused values using `_`
for (_, (key, _)) in enumerate(views) {
  self.statsView.addConstraints(
    NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-60-[\(key)(>=100)]-60-|", options: nil, metrics: nil, views: views))
}


// Another example creating an "inline-block" effect
// Screenshot: http://cl.ly/image/1U1b0F2X0Y1U

let metrics = [
 "vSpace": 6,
 "hSpace": 12
]

self.statsView.addConstraints(
  NSLayoutConstraint.constraintsWithVisualFormat(
    "H:|-hSpace-[red]-hSpace-[blue(==red)]-hSpace-[yellow(==red)]-hSpace-|", options: nil, metrics: metrics, views: views))

for (_, (key, _)) in enumerate(views) {
 self.statsView.addConstraints(
   NSLayoutConstraint.constraintsWithVisualFormat(
     "V:|-vSpace-[\(key)]-vSpace-|", options: nil, metrics: metrics, views: views))
}