minor code refactoring

Sources/Inheritence.swift

@@ -4,11 +4,12 @@ class BlockContext {
   // contains mapping of block names to their nodes and templates where they are defined
   var blocks: [String: [BlockNode]]
 
-  init(blocks: [String: [BlockNode]]) {
-    self.blocks = blocks
+  init(blocks: [String: BlockNode]) {
+    self.blocks = [:]
+    blocks.forEach { self.blocks[$0.key] = [$0.value] }
   }
 
-  func pushBlock(_ block: BlockNode, named blockName: String) {
+  func push(_ block: BlockNode, forKey blockName: String) {
     if var blocks = blocks[blockName] {
       blocks.append(block)
       self.blocks[blockName] = blocks
@@ -17,7 +18,7 @@ class BlockContext {
     }
   }
 
-  func popBlock(named blockName: String) -> BlockNode? {
+  func pop(_ blockName: String) -> BlockNode? {
     if var blocks = blocks[blockName] {
       let block = blocks.removeFirst()
       if blocks.isEmpty {
@@ -88,14 +89,12 @@ class ExtendsNode : NodeType {
     let baseTemplate = try context.environment.loadTemplate(name: templateName)
 
     let blockContext: BlockContext
-    if let _blockContext = context[BlockContext.contextKey] as? BlockContext {
-      blockContext = _blockContext
+    if let currentBlockContext = context[BlockContext.contextKey] as? BlockContext {
+      blockContext = currentBlockContext
       for (name, block) in blocks {
-        blockContext.pushBlock(block, named: name)
+        blockContext.push(block, forKey: name)
       }
     } else {
-      var blocks = [String: [BlockNode]]()
-      self.blocks.forEach { blocks[$0.key] = [$0.value] }
       blockContext = BlockContext(blocks: blocks)
     }
 
@@ -144,48 +143,47 @@ class BlockNode : NodeType {
   }
 
   func render(_ context: Context) throws -> String {
-    if let blockContext = context[BlockContext.contextKey] as? BlockContext, let child = blockContext.popBlock(named: name) {
-      // child node is a block node from child template that extends this node (has the same name)
-
-      var newContext: [String: Any] = [BlockContext.contextKey: blockContext]
-
-      if let blockSuperNode = child.nodes.first(where: {
-        if case .variable(let variable, _)? = $0.token, variable == "block.super" { return true }
-        else { return false}
-      }) {
-        do {
-          // render current (base) node so that its content can be used as part of node that extends it
-          newContext["block"] = ["super": try self.render(context)]
-        } catch {
-          if let error = error as? TemplateSyntaxError {
-            throw TemplateSyntaxError(
-              reason: error.reason,
-              token: blockSuperNode.token,
-              stackTrace: error.allTokens)
-          } else {
-            throw TemplateSyntaxError(
-              reason: "\(error)",
-              token: blockSuperNode.token,
-              stackTrace: [])
-          }
-        }
-      }
-
+    if let blockContext = context[BlockContext.contextKey] as? BlockContext, let child = blockContext.pop(name) {
+      let childContext = try self.childContext(child, blockContext: blockContext, context: context)
       // render extension node
       do {
-        return try context.push(dictionary: newContext) {
+        return try context.push(dictionary: childContext) {
           return try child.render(context)
         }
       } catch {
-        if var error = error as? TemplateSyntaxError {
-          error.token = error.token ?? child.token
-          throw error
-        } else {
-          throw error
-        }
+        throw error.withToken(child.token)
       }
     }
 
     return try renderNodes(nodes, context)
   }
+
+  // child node is a block node from child template that extends this node (has the same name)
+  func childContext(_ child: BlockNode, blockContext: BlockContext, context: Context) throws -> [String: Any?] {
+    var childContext: [String: Any?] = [BlockContext.contextKey: blockContext]
+
+    if let blockSuperNode = child.nodes.first(where: {
+      if case .variable(let variable, _)? = $0.token, variable == "block.super" { return true }
+      else { return false}
+    }) {
+      do {
+        // render base node so that its content can be used as part of child node that extends it
+        childContext["block"] = ["super": try self.render(context)]
+      } catch {
+        if let error = error as? TemplateSyntaxError {
+          throw TemplateSyntaxError(
+            reason: error.reason,
+            token: blockSuperNode.token,
+            stackTrace: error.allTokens)
+        } else {
+          throw TemplateSyntaxError(
+            reason: "\(error)",
+            token: blockSuperNode.token,
+            stackTrace: [])
+        }
+      }
+    }
+    return childContext
+  }
+
 }