Non verbose way to create constraints and work with anchors.

This framework provides:

• Operators (custom and overloads) for anchors and constraints. Let you define constraints simply and clearly.

  view.topAnchor == superview.topAnchor ~ .high + 10
  

  It also lets you store the constraint after definition.

  let constraint = view.topAnchor == superview.topAnchor ~ .high ↑ "CustomIdentifier"
  

• Anchor groups. Autolayout provide group of anchors that usually perform similar operations. Such as horizontal anchors (left, right), directional anchors (leading, trailing), edge anchors (top, left, bottom, right), etc.

  scrollview.edgeAnchor == superview.edgeAnchor
  

  It lets you work with anchor groups similarly than you would work with simple anchors.

  scrollview.edgeAnchor == superview.edgeAnchor + 5 ~ .low
  

• Constraint containers. It let you store or access easily constraints created through anchor groups.

  let container = view.directionalEdgeAnchor >= superview.directionalEdgeAnchor + 3 ~ .required
  container.leading.constant = 10
  container.bottom.isActive = true
  

  Autolayout lets you perform normal constraint operations on the whole constraint container.

  container.constant = 10
  

• Compile-time constraint creation checks. You can only perform operations on compatible types. For example, none of following lines will compile:

  view.horizontalAnchor == superview.directionalAnchor
  view.sizeAnchor >= superview.verticalAnchor
  

License

This code and tool is under the MIT License. See LICENSE file in this repository.

Any ideas and contributions welcome!

Disclaimer

This framework was initially influenced by Anchorage by Raizlabs. Although the syntax is similar, Autolayout provide a completely different internals and generics system to facilitate compile-time checks and group operations (such as activity or constant settings).

In any case, Anchorage is still a great tool that I thoroughly recommend to anyone ;)