[Template] Expose token parser

Stencil/Context.swift

@@ -8,6 +8,10 @@ public class Context : Equatable {
         dictionaries = [dictionary]
     }
 
+    public init() {
+        dictionaries = []
+    }
+
     public subscript(key: String) -> AnyObject? {
         get {
             for dictionary in reverse(dictionaries) {

Stencil/Template.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 public class Template {
-    let parser:TokenParser
+    public let parser:TokenParser
 
     public convenience init?(named:String) {
         self.init(named:named, inBundle:nil)
@@ -45,4 +45,9 @@ public class Template {
                 return .Error(error:error)
         }
     }
+
+    public func render() -> Result {
+        let context = Context()
+        return render(context)
+    }
 }

StencilTests/StencilTests.swift

@@ -20,6 +20,12 @@ func assertFailure(result:TokenParser.Results, description:String) {
     }
 }
 
+class CustomNode : Node {
+    func render(context:Context) -> (String?, Error?) {
+        return ("Hello World", nil)
+    }
+}
+
 class StencilTests: XCTestCase {
     func testReadmeExample() {
         let templateString = "There are {{ articles.count }} articles.\n" +
@@ -46,4 +52,16 @@ class StencilTests: XCTestCase {
 
         XCTAssertEqual(result, Result.Success(string: fixture))
     }
+
+    func testCustomTag() {
+        let templateString = "{% custom %}"
+        let template = Template(templateString:templateString)
+
+        template.parser.registerTag("custom") { parser, token in
+            return .Success(node:CustomNode())
+        }
+
+        let result = template.render()
+        XCTAssertEqual(result, Result.Success(string: "Hello World"))
+    }
 }