Added Result class to make writing failure resistant code easier

lib/cyberarm_engine.rb

@@ -9,6 +9,7 @@ require "json"
 
 require_relative "cyberarm_engine/version"
 require_relative "cyberarm_engine/stats"
+require_relative "cyberarm_engine/result"
 
 require_relative "cyberarm_engine/common"
 

lib/cyberarm_engine/result.rb

@@ -0,0 +1,20 @@
+module CyberarmEngine
+  # result pattern
+  class Result
+    attr_accessor :error, :data
+
+    def initialize(data: nil, error: nil)
+      @data = data
+      @error = error
+    end
+
+    def okay?
+      !@error
+    end
+
+    def error?
+      @error || @data.nil?
+    end
+  end
+end
+