       guard let action = actionMap[key] else {
         return ParsingError(message: "Can't parse key '\(key)'") }
 
-      let error = action(valueYaml)
-      if error != nil { return error }
+      if let error = action(valueYaml) {
+        return error
+      }
     }// for
 
     return nil

      return ParsingError(message: error)
    }

    // Map names to processors
    let actionMap = [
      "compiler_options":       self.parseCompilerOptions,
      "dependencies":           self.parseDependencies,

      return ParsingError(message: "Invalid target type; expected string")
    }

    guard let type = TargetType(string: typeString) else {
      return ParsingError(message: "Invalid target type '\(typeString)'")
    }

