Merge pull request #67 from ikesyo/ifnode-evaluate-bool-value

[IfNode] Accept and evaluate a `Bool` value as a valid expression

Sources/IfTag.swift

@@ -29,7 +29,7 @@ public class IfNode : NodeType {
   public class func parse_ifnot(parser:TokenParser, token:Token) throws -> NodeType {
     let components = token.components()
     guard components.count == 2 else {
-      throw TemplateSyntaxError("'ifnot' statements should use the following 'if condition' `\(token.contents)`.")
+      throw TemplateSyntaxError("'ifnot' statements should use the following 'ifnot condition' `\(token.contents)`.")
     }
     let variable = components[1]
     var trueNodes = [NodeType]()
@@ -63,6 +63,8 @@ public class IfNode : NodeType {
       truthy = !result.isEmpty
     } else if let result = result as? [String:Any] {
       truthy = !result.isEmpty
+    } else if let result = result as? Bool {
+      truthy = result
     } else if result != nil {
       truthy = true
     }

Tests/Nodes/IfNodeSpec.swift

@@ -73,14 +73,26 @@ func testIfNode() {
     }
 
     $0.describe("rendering") {
-      let context = Context(dictionary: ["items": true])
-
       $0.it("renders the truth when expression evaluates to true") {
+        let context = Context(dictionary: ["items": true])
         let node = IfNode(variable: "items", trueNodes: [TextNode(text: "true")], falseNodes: [TextNode(text: "false")])
         try expect(try node.render(context)) == "true"
       }
 
       $0.it("renders the false when expression evaluates to false") {
+        let context = Context(dictionary: ["items": false])
+        let node = IfNode(variable: "items", trueNodes: [TextNode(text: "true")], falseNodes: [TextNode(text: "false")])
+        try expect(try node.render(context)) == "false"
+      }
+
+      $0.it("renders the truth when expression is not nil") {
+        let context = Context(dictionary: ["known": "known"])
+        let node = IfNode(variable: "known", trueNodes: [TextNode(text: "true")], falseNodes: [TextNode(text: "false")])
+        try expect(try node.render(context)) == "true"
+      }
+
+      $0.it("renders the false when expression is nil") {
+        let context = Context(dictionary: [:])
         let node = IfNode(variable: "unknown", trueNodes: [TextNode(text: "true")], falseNodes: [TextNode(text: "false")])
         try expect(try node.render(context)) == "false"
       }