Remove custom Result type and throw errors

Stencil/TemplateLoader/Inheritence.swift

@@ -24,36 +24,32 @@ func any<Element>(elements:[Element], closure:(Element -> Bool)) -> Element? {
   return nil
 }
 
-class ExtendsNode : Node {
+class ExtendsNode : NodeType {
   let templateName:String
   let blocks:[String:BlockNode]
 
-  class func parse(parser:TokenParser, token:Token) -> TokenParser.Result {
+  class func parse(parser:TokenParser, token:Token) throws -> NodeType {
     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"))
+      throw TemplateSyntaxError("'extends' 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 = nodes.filter { node in node is BlockNode }
-
-      let nodes = blockNodes.reduce([String:BlockNode](), combine: { (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)
+    let parsedNodes = try parser.parse()
+    if (any(parsedNodes) { ($0 as? ExtendsNode) != nil }) != nil {
+      throw TemplateSyntaxError("'extends' cannot appear more than once in the same template")
     }
+
+    let blockNodes = parsedNodes.filter { node in node is BlockNode }
+
+    let nodes = blockNodes.reduce([String:BlockNode](), combine: { (accumulator, node:NodeType) -> [String:BlockNode] in
+      let node = (node as! BlockNode)
+      var dict = accumulator
+      dict[node.name] = node
+      return dict
+    })
+
+    return ExtendsNode(templateName: bits[1], blocks: nodes)
   }
 
   init(templateName:String, blocks:[String:BlockNode]) {
@@ -61,12 +57,12 @@ class ExtendsNode : Node {
     self.blocks = blocks
   }
 
-  func render(context: Context) -> Result {
+  func render(context: Context) throws -> String {
     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)
+        let result = try template.render(context)
         context.pop()
         return result
       }
@@ -74,51 +70,39 @@ class ExtendsNode : Node {
       let paths:String = loader.paths.map { path in
         return path.description
         }.joinWithSeparator(", ")
-      let error = "Template '\(templateName)' not found in \(paths)"
-      return .Error(error)
+      throw TemplateSyntaxError("'\(templateName)' template not found in \(paths)")
     }
 
-    let error = "Template loader not in context"
-    return .Error(error)
+    throw TemplateSyntaxError("Template loader not in context")
   }
 }
 
-class BlockNode : Node {
+class BlockNode : NodeType {
   let name:String
-  let nodes:[Node]
+  let nodes:[NodeType]
 
-  class func parse(parser:TokenParser, token:Token) -> TokenParser.Result {
+  class func parse(parser:TokenParser, token:Token) throws -> NodeType {
     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"))
+      throw TemplateSyntaxError("'block' 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))
+    let nodes = try parser.parse(until(["endblock"]))
+    return BlockNode(name:blockName, nodes:nodes)
   }
 
-  init(name:String, nodes:[Node]) {
+  init(name:String, nodes:[NodeType]) {
     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)
-      }
+  func render(context: Context) throws -> String {
+    if let blockContext = context[BlockContext.contextKey] as? BlockContext, node = blockContext.pop(name) {
+      return try node.render(context)
     }
 
-    return renderNodes(nodes, context: context)
+    return try renderNodes(nodes, context)
   }
 }