// 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) )

// using MiniLayout:
addConstrainedChild(vc, constrain: .bottomMargin, .top, .left, .right)
 
// without MiniLayout:
addChild(vc)
view.addSubview(vc.view)
vc.view.setTranslatesAutoresizingMaskIntoConstraints(false)
view.addConstraint( NSLayoutConstraint(item: vc.view, attribute: .bottomMargin, relatedBy: .equal, toItem: view, attribute: .bottomMargin, multiplier: 1, constant: 0) )
view.addConstraint( NSLayoutConstraint(item: vc.view, attribute: .top, relatedBy: .equal, toItem: view, attribute: .top, multiplier: 1, constant: 0) )
view.addConstraint( NSLayoutConstraint(item: vc.view, attribute: .left, relatedBy: .equal, toItem: view, attribute: .left, multiplier: 1, constant: 0) )
view.addConstraint( NSLayoutConstraint(item: vc.view, attribute: .right, relatedBy: .equal, toItem: view, attribute: .right, multiplier: 1, constant: 0) )
vc.didMove(toParent: self)