Include template inheritence

Closes #15

Stencil.xcodeproj/project.pbxproj

@@ -8,6 +8,10 @@
 
 /* Begin PBXBuildFile section */
 		1474245D3CE34A8BC76F8D20 /* Pods_StencilTests.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 40E4E61A4F4EA12FE3FA6E39 /* Pods_StencilTests.framework */; settings = {ATTRIBUTES = (Weak, ); }; };
+		27A848E41B42240E004ACA13 /* Inheritence.swift in Sources */ = {isa = PBXBuildFile; fileRef = 27A848E31B42240E004ACA13 /* Inheritence.swift */; };
+		27A848E91B42242C004ACA13 /* base.html in Resources */ = {isa = PBXBuildFile; fileRef = 27A848E71B42242C004ACA13 /* base.html */; };
+		27A848EA1B42242C004ACA13 /* child.html in Resources */ = {isa = PBXBuildFile; fileRef = 27A848E81B42242C004ACA13 /* child.html */; };
+		27A848EC1B42247D004ACA13 /* InheritenceTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 27A848EB1B42247D004ACA13 /* InheritenceTests.swift */; };
 		27CE0ADE1A50BEC3004A105B /* TemplateLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 27CE0ADD1A50BEC3004A105B /* TemplateLoader.swift */; };
 		27CE0AE01A50BF05004A105B /* TemplateLoaderTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 27CE0ADF1A50BF05004A105B /* TemplateLoaderTests.swift */; };
 		27CE0AFA1A50C963004A105B /* test.html in Resources */ = {isa = PBXBuildFile; fileRef = 27CE0AF91A50C963004A105B /* test.html */; };
@@ -45,6 +49,10 @@
 
 /* Begin PBXFileReference section */
 		216AE96E764D5BD92D11049B /* Pods-Stencil.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Stencil.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Stencil/Pods-Stencil.debug.xcconfig"; sourceTree = "<group>"; };
+		27A848E31B42240E004ACA13 /* Inheritence.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Inheritence.swift; sourceTree = "<group>"; };
+		27A848E71B42242C004ACA13 /* base.html */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; path = base.html; sourceTree = "<group>"; };
+		27A848E81B42242C004ACA13 /* child.html */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; path = child.html; sourceTree = "<group>"; };
+		27A848EB1B42247D004ACA13 /* InheritenceTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = InheritenceTests.swift; sourceTree = "<group>"; };
 		27CE0ADD1A50BEC3004A105B /* TemplateLoader.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TemplateLoader.swift; sourceTree = "<group>"; };
 		27CE0ADF1A50BF05004A105B /* TemplateLoaderTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TemplateLoaderTests.swift; sourceTree = "<group>"; };
 		27CE0AF91A50C963004A105B /* test.html */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; path = test.html; sourceTree = "<group>"; };
@@ -102,6 +110,7 @@
 			isa = PBXGroup;
 			children = (
 				27CE0B001A50CBD1004A105B /* Include.swift */,
+				27A848E31B42240E004ACA13 /* Inheritence.swift */,
 			);
 			path = TemplateLoader;
 			sourceTree = "<group>";
@@ -110,6 +119,7 @@
 			isa = PBXGroup;
 			children = (
 				27CE0B031A50CBEA004A105B /* IncludeTests.swift */,
+				27A848EB1B42247D004ACA13 /* InheritenceTests.swift */,
 			);
 			path = TemplateLoader;
 			sourceTree = "<group>";
@@ -176,6 +186,8 @@
 				27CE0ADF1A50BF05004A105B /* TemplateLoaderTests.swift */,
 				27CE0B021A50CBEA004A105B /* TemplateLoader */,
 				27CE0AF91A50C963004A105B /* test.html */,
+				27A848E71B42242C004ACA13 /* base.html */,
+				27A848E81B42242C004ACA13 /* child.html */,
 				77FAAE6219F91E480029DC5E /* Supporting Files */,
 			);
 			path = StencilTests;
@@ -312,6 +324,8 @@
 			buildActionMask = 2147483647;
 			files = (
 				27CE0AFA1A50C963004A105B /* test.html in Resources */,
+				27A848EA1B42242C004ACA13 /* child.html in Resources */,
+				27A848E91B42242C004ACA13 /* base.html in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -410,6 +424,7 @@
 				71CE4C0A19FD29D000B9E0C5 /* Result.swift in Sources */,
 				7725B3D519F9438F002CF74B /* Node.swift in Sources */,
 				27CE0ADE1A50BEC3004A105B /* TemplateLoader.swift in Sources */,
+				27A848E41B42240E004ACA13 /* Inheritence.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -419,6 +434,7 @@
 			files = (
 				77FAAE6519F91E480029DC5E /* StencilTests.swift in Sources */,
 				7725B3D319F9437F002CF74B /* NodeTests.swift in Sources */,
+				27A848EC1B42247D004ACA13 /* InheritenceTests.swift in Sources */,
 				27CE0AE01A50BF05004A105B /* TemplateLoaderTests.swift in Sources */,
 				7725B3D919F94A61002CF74B /* ParserTests.swift in Sources */,
 				77EB082719F96E9C001870F1 /* TemplateTests.swift in Sources */,

Stencil/Context.swift

@@ -35,10 +35,10 @@ public class Context : Equatable {
   }
 
   public func push() {
-    push(Dictionary<String, String>())
+    push(Dictionary<String, AnyObject>())
   }
 
-  public func push(dictionary:Dictionary<String, String>) {
+  public func push(dictionary:Dictionary<String, AnyObject>) {
     dictionaries.append(dictionary)
   }
 

Stencil/Parser.swift

@@ -37,6 +37,8 @@ public class TokenParser {
     registerTag("ifnot", parser: IfNode.parse_ifnot)
     registerTag("now", parser: NowNode.parse)
     registerTag("include", parser: IncludeNode.parse)
+    registerTag("extends", parser: ExtendsNode.parse)
+    registerTag("block", parser: BlockNode.parse)
   }
 
   /// Registers a new template tag

Stencil/TemplateLoader/Inheritence.swift

@@ -0,0 +1,124 @@
+import Foundation
+
+class BlockContext {
+  class var contextKey:String { return "block_context" }
+
+  var blocks:[String:BlockNode]
+
+  init(blocks:[String:BlockNode]) {
+    self.blocks = blocks
+  }
+
+  func pop(blockName:String) -> BlockNode? {
+    return blocks.removeValueForKey(blockName)
+  }
+}
+
+func any<Element>(elements:[Element], closure:(Element -> Bool)) -> Element? {
+  for element in elements {
+    if closure(element) {
+      return element
+    }
+  }
+
+  return nil
+}
+
+class ExtendsNode : Node {
+  let templateName:String
+  let blocks:[String:BlockNode]
+
+  class func parse(parser:TokenParser, token:Token) -> TokenParser.Result {
+    let bits = token.contents.componentsSeparatedByString("\"")
+
+    if bits.count != 3 {
+      return .Error(error:NodeError(token: token, message: "Tag takes one argument, the template file to be extended"))
+    }
+
+    switch parser.parse() {
+    case .Success(let nodes):
+      if (any(nodes) { ($0 as? ExtendsNode) != nil }) != nil {
+        return .Error(error:"'extends' cannot appear more than once in the same template")
+      }
+
+      let blockNodes = filter(nodes) { node in node is BlockNode }
+
+      let nodes = reduce(blockNodes, [String:BlockNode](), { (accumulator, node:Node) -> [String:BlockNode] in
+        let node = (node as! BlockNode)
+        var dict = accumulator
+        dict[node.name] = node
+        return dict
+      })
+
+      return .Success(node:ExtendsNode(templateName: bits[1], blocks: nodes))
+    case .Error(let error):
+      return .Error(error:error)
+    }
+  }
+
+  init(templateName:String, blocks:[String:BlockNode]) {
+    self.templateName = templateName
+    self.blocks = blocks
+  }
+
+  func render(context: Context) -> Result {
+    if let loader =  context["loader"] as? TemplateLoader {
+      if let template = loader.loadTemplate(templateName) {
+        let blockContext = BlockContext(blocks: blocks)
+        context.push([BlockContext.contextKey: blockContext])
+        let result = template.render(context)
+        context.pop()
+        return result
+      }
+
+      let paths:String = join(", ", loader.paths.map { path in
+        return path.description
+        })
+      let error = "Template '\(templateName)' not found in \(paths)"
+      return .Error(error)
+    }
+
+    let error = "Template loader not in context"
+    return .Error(error)
+  }
+}
+
+class BlockNode : Node {
+  let name:String
+  let nodes:[Node]
+
+  class func parse(parser:TokenParser, token:Token) -> TokenParser.Result {
+    let bits = token.components()
+
+    if bits.count != 2 {
+      return .Error(error:NodeError(token: token, message: "Tag takes one argument, the template file to be included"))
+    }
+
+    let blockName = bits[1]
+    var nodes = [Node]()
+
+    switch parser.parse(until(["endblock"])) {
+    case .Success(let blockNodes):
+      nodes = blockNodes
+    case .Error(let error):
+      return .Error(error: error)
+    }
+
+    return .Success(node:BlockNode(name:blockName, nodes:nodes))
+  }
+
+  init(name:String, nodes:[Node]) {
+    self.name = name
+    self.nodes = nodes
+  }
+
+  func render(context: Context) -> Result {
+    if let blockContext = context[BlockContext.contextKey] as? BlockContext {
+      if let node = blockContext.pop(name) {
+        return node.render(context)
+      }
+    }
+
+    return renderNodes(nodes, context)
+  }
+}

StencilTests/TemplateLoader/InheritenceTests.swift

@@ -0,0 +1,51 @@
+import Foundation
+import XCTest
+import Stencil
+import PathKit
+
+class InheritenceTests: NodeTests {
+  var loader:TemplateLoader!
+
+  override func setUp() {
+    super.setUp()
+
+    let path = (Path(__FILE__) + Path("../..")).absolute()
+    loader = TemplateLoader(paths: [path])
+  }
+
+  func testInheritence() {
+    context = Context(dictionary: ["loader": loader])
+    let template = loader.loadTemplate("child.html")!
+    let result = template.render(context)
+
+    switch result {
+    case .Success(let rendered):
+      XCTAssertEqual(rendered, "Header\nChild")
+    case .Error(let error):
+      XCTAssert(false, "Unexpected error")
+    }
+  }
+}
+
+//class BlockNodeTests: NodeTests {
+//    func testBlockNodeWithoutChildren() {
+//        let context = Context()
+//        let block = BlockNode(name:"header", nodes:[TextNode(text: "contents")])
+//        let result = block.render(context)
+//
+//        assertSuccess(result) { rendered in
+//            XCTAssertEqual(rendered, "contents")
+//        }
+//    }
+//
+//    func testBlockNodeWithChild() {
+//        let context = Context()
+//        let node = BlockNode(name:"header", nodes:[TextNode(text: "contents")])
+//        let childBlock = BlockNode(name: "header", nodes: [TextNode(text: "child contents")])
+//        let result = node.render(context)
+//
+//        assertSuccess(result) { rendered in
+//            XCTAssertEqual(rendered, "child contents")
+//        }
+//    }
+//}

StencilTests/base.html

@@ -0,0 +1,2 @@
+{% block header %}Header{% endblock %}
+{% block body %}Body{% endblock %}

StencilTests/child.html

@@ -0,0 +1,2 @@
+{% extends "base.html" %}
+{% block body %}Child{% endblock %}