Add support for UIViewController layout guides

Author: indragiek

README.md

@@ -1,6 +1,6 @@
 ## SwiftAutoLayout
 
-SwiftAutoLayout is a tiny DSL for Autolayout (~90 LOC), intended to provide a more declarative way to express layout constraints. Here's a quick example:
+SwiftAutoLayout is a tiny DSL for Autolayout intended to provide a more declarative way to express layout constraints. Here's a quick example:
 
 ```swift
 // this:
@@ -23,6 +23,8 @@ SwiftAutoLayout allows you to more effectively communicate the intent of a const
 
 Layout attributes are defined as properties added in extensions of `UIView` and `UILayoutGuide` on iOS and `NSView` and `NSLayoutGuide` on OS X. For example, `UIView.width` and `UIView.height` represent `NSLayoutAttribute.Width` and `NSLayoutAttribute.Height`, respectively.
 
+Layout guides (conforming to `UILayoutSupport`) in `UIViewController` are also supported using the `topLayoutGuideTop`, `topLayoutGuideBottom`, `bottomLayoutGuideTop`, and `bottomLayoutGuideBottom` properties.
+
 ### Relations
 
 Relations are expressed using the overloaded operators `==` (`NSLayoutRelation.Equal`), `>=` (`NSLayoutRelation.GreaterThanOrEqual`), and `<=` (`NSLayoutRelation.LessThanOrEqual`). 

SwiftAutoLayout/SwiftAutoLayout.swift

@@ -90,23 +90,43 @@ public func <=(lhs: LayoutItem<Dimension>, rhs: CGFloat) -> NSLayoutConstraint {
     return lhs.constrain(rhs, relation: .LessThanOrEqual)
 }
 
+private func layoutItem<C>(item: AnyObject, _ attribute: NSLayoutAttribute) -> LayoutItem<C> {
+    return LayoutItem(item: item, attribute: attribute, multiplier: 1.0, constant: 0.0)
+}
+
 public extension LayoutRegion {
-    private func layoutItem<C>(attribute: NSLayoutAttribute) -> LayoutItem<C> {
-        return LayoutItem(item: self, attribute: attribute, multiplier: 1.0, constant: 0.0)
+    public var left: LayoutItem<XAxis> { return layoutItem(self, .Left) }
+    public var right: LayoutItem<XAxis> { return layoutItem(self, .Right) }
+    public var top: LayoutItem<YAxis> { return layoutItem(self, .Top) }
+    public var bottom: LayoutItem<YAxis> { return layoutItem(self, .Bottom) }
+    public var leading: LayoutItem<XAxis> { return layoutItem(self, .Leading) }
+    public var trailing: LayoutItem<XAxis> { return layoutItem(self, .Trailing) }
+    public var width: LayoutItem<Dimension> { return layoutItem(self, .Width) }
+    public var height: LayoutItem<Dimension> { return layoutItem(self, .Height) }
+    public var centerX: LayoutItem<XAxis> { return layoutItem(self, .CenterX) }
+    public var centerY: LayoutItem<YAxis> { return layoutItem(self, .CenterY) }
+    public var baseline: LayoutItem<YAxis> { return layoutItem(self, .Baseline) }
+}
+
+#if os(iOS)
+public extension UIViewController {
+    public var topLayoutGuideTop: LayoutItem<YAxis> {
+        return layoutItem(topLayoutGuide, .Top)
+    }
+    
+    public var topLayoutGuideBottom: LayoutItem<YAxis> {
+        return layoutItem(topLayoutGuide, .Bottom)
+    }
+    
+    public var bottomLayoutGuideTop: LayoutItem<YAxis> {
+        return layoutItem(bottomLayoutGuide, .Top)
     }
 
-    public var left: LayoutItem<XAxis> { return layoutItem(.Left) }
-    public var right: LayoutItem<XAxis> { return layoutItem(.Right) }
-    public var top: LayoutItem<YAxis> { return layoutItem(.Top) }
-    public var bottom: LayoutItem<YAxis> { return layoutItem(.Bottom) }
-    public var leading: LayoutItem<XAxis> { return layoutItem(.Leading) }
-    public var trailing: LayoutItem<XAxis> { return layoutItem(.Trailing) }
-    public var width: LayoutItem<Dimension> { return layoutItem(.Width) }
-    public var height: LayoutItem<Dimension> { return layoutItem(.Height) }
-    public var centerX: LayoutItem<XAxis> { return layoutItem(.CenterX) }
-    public var centerY: LayoutItem<YAxis> { return layoutItem(.CenterY) }
-    public var baseline: LayoutItem<YAxis> { return layoutItem(.Baseline) }
+    public var bottomLayoutGuideBottom: LayoutItem<YAxis> {
+        return layoutItem(bottomLayoutGuide, .Bottom)
+    }
 }
+#endif
 
 infix operator ~ { associativity left precedence 120 }
 

SwiftAutoLayoutTests/SwiftAutoLayoutTests.swift

@@ -4,11 +4,19 @@
 import XCTest
 import SwiftAutoLayout
 
+#if os(iOS)
+private class ViewController: UIViewController {
+    private override func loadView() {
+        self.view = UIView(frame: CGRectZero)
+    }
+}
+#endif
+
 class SwiftAutoLayoutTests: XCTestCase {
     let view1 = View(frame: CGRectZero)
     let view2 = View(frame: CGRectZero)
 
-    func testAttributeValues() {
+    func testViewAttributeValues() {
         XCTAssertEqual(view1.left.attribute, NSLayoutAttribute.Left)
         XCTAssertEqual(view1.right.attribute, NSLayoutAttribute.Right)
         XCTAssertEqual(view1.top.attribute, NSLayoutAttribute.Top)
@@ -22,6 +30,17 @@ class SwiftAutoLayoutTests: XCTestCase {
         XCTAssertEqual(view1.baseline.attribute, NSLayoutAttribute.Baseline)
     }
 
+    #if os(iOS)
+    func testViewControllerAttributeValues() {
+        let viewController = ViewController()
+        print(viewController.view) // Load the view
+        XCTAssertEqual(viewController.topLayoutGuideTop.attribute, NSLayoutAttribute.Top)
+        XCTAssertEqual(viewController.topLayoutGuideBottom.attribute, NSLayoutAttribute.Bottom)
+        XCTAssertEqual(viewController.bottomLayoutGuideTop.attribute, NSLayoutAttribute.Top)
+        XCTAssertEqual(viewController.bottomLayoutGuideBottom.attribute, NSLayoutAttribute.Bottom)
+    }
+    #endif
+    
     func testEqual() {
         let constraint = view1.left == view2.right;
         XCTAssertEqual(constraint.firstItem as? View, view1)