added recursive resolution for superclass properties

Sources/Variable.swift

@@ -100,15 +100,9 @@ public struct Variable : Equatable, Resolvable {
         current = object.value(forKey: bit)
 #endif
       } else if let value = current {
-        let mirror = Mirror(reflecting: value)
-        current = mirror.descendant(bit)
-
+        current = Mirror(reflecting: value).getValue(for: bit)
         if current == nil {
           return nil
-          // mirror returns non-nil value even for nil-containing properties
-          // so we have to check if its value is actually nil or not
-        } else if let current = current, String(describing: current) == "nil" {
-          return nil
         }
       } else {
         return nil
@@ -179,3 +173,18 @@ func parseFilterComponents(token: String) -> (String, [Variable]) {
     .map { Variable($0) }
   return (name, variables)
 }
+
+extension Mirror {
+  func getValue(for key: String) -> Any? {
+    let result = descendant(key)
+    if result == nil {
+      // go through inheritance chain to reach superclass properties
+      return superclassMirror?.getValue(for: key)
+    } else if let result = result, String(describing: result) == "nil" {
+      // mirror returns non-nil value even for nil-containing properties
+      // so we have to check if its value is actually nil or not
+      return nil
+    }
+    return result
+  }
+}

Tests/StencilTests/VariableSpec.swift

@@ -4,7 +4,10 @@ import Spectre
 
 
 #if os(OSX)
-@objc class Object : NSObject {
+@objc class Superclass: NSObject {
+  let name = "Foo"
+}
+@objc class Object : Superclass {
   let title = "Hello World"
 }
 #endif
@@ -17,6 +20,13 @@ fileprivate struct Article {
   let author: Person
 }
 
+fileprivate class WebSite {
+  let url: String = "blog.com"
+}
+
+fileprivate class Blog: WebSite {
+  let articles: [Article] = [Article(author: Person(name: "Kyle"))]
+}
 
 func testVariable() {
   describe("Variable") {
@@ -35,6 +45,7 @@ func testVariable() {
 #if os(OSX)
     context["object"] = Object()
 #endif
+    context["blog"] = Blog()
 
     $0.it("can resolve a string literal with double quotes") {
       let variable = Variable("\"name\"")
@@ -122,6 +133,25 @@ func testVariable() {
       let result = try variable.resolve(context) as? String
       try expect(result) == "Hello World"
     }
+
+    $0.it("can resolve a superclass value via KVO") {
+      let variable = Variable("object.name")
+      let result = try variable.resolve(context) as? String
+      try expect(result) == "Foo"
+    }
 #endif
+    
+    $0.it("can resolve a value via reflection") {
+      let variable = Variable("blog.articles.0.author.name")
+      let result = try variable.resolve(context) as? String
+      try expect(result) == "Kyle"
+    }
+
+    $0.it("can resolve a superclass value via reflection") {
+      let variable = Variable("blog.url")
+      let result = try variable.resolve(context) as? String
+      try expect(result) == "blog.com"
+    }
+
   }
 }