// using MiniLayout:
view.constrain(label, at: .Leading, to: textField)
view.constrain(textField, at: .Top, to: label, at: .Bottom, diff: 8)
 
// without MiniLayout:
view.addConstraint( NSLayoutConstraint(item: label, attribute: .Leading, relatedBy: Equal, toItem: textField, attribute: .Leading, multiplier: 1, constant: 0) )
view.addConstraint( NSLayoutConstraint(item: textField, attribute: .Top, relatedBy: Equal, toItem: label, attribute: .Bottom, multiplier: 1, constant: 8) )

// using MiniLayout:
view.addConstrainedSubview(button, constrain: .CenterX, .CenterY)
 
// without MiniLayout:
view.addSubview(button)
button.setTranslatesAutoresizingMaskIntoConstraints(false)
view.addConstraint( NSLayoutConstraint(item: button, attribute: .CenterX, relatedBy: Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 0) )
view.addConstraint( NSLayoutConstraint(item: button, attribute: .CenterY, relatedBy: Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 0) )