constraint-helper.swift

// Would you rather use this:

NSLayoutConstraint(item: label, attribute: .Leading, relatedBy: .Equal, toItem: button, attribute: .Trailing, multiplier: 1, constant: 0).active = true

// or this?

label.constrain(.Leading, .Equal, to: button, .Trailing, plus: 20)



public extension NSView
{
    func constrain(
        attribute: NSLayoutAttribute,
        _ relation: NSLayoutRelation,
        to otherView: NSView,
        _ otherAttribute: NSLayoutAttribute,
        times multiplier: CGFloat = 1,
        plus constant: CGFloat = 0
        atPriority priority: NSLayoutPriority = 1000) -> NSLayoutConstraint
    {
        let c = NSLayoutConstraint(
            item: self,
            attribute: attribute,
            relatedBy: relation,
            toItem: otherView,
            attribute: otherAttribute,
            multiplier: multiplier,
            constant: constant)
        c.priority = priority
        c.active = true
        return c
    }
}

Awesomeeee

If you like this, check these out:
https://github.com/robb/Cartography
https://github.com/Rightpoint/Anchorage