Fix Issue #15

lib/rubies/game.rb

@@ -107,6 +107,16 @@ def itsright
       puts "Correct!".colorize(:green)
     end
 
+    def cheater
+      @num_wrong += 1
+      puts "Please provide an answer "\
+            "that operates on the given values. ".colorize(:light_red)
+      puts
+      puts "Try not to directly reference the value directly, ".colorize(:light_red)
+      puts
+      puts "Instead, try accessing the value by its index or key!".colorize(:light_red)
+    end
+
     def prompter(answer)
       print "Write ruby code to find the following value".colorize(:light_blue)
       print " (or enter ".colorize(:light_blue) + 'NEW'.colorize(:green)
@@ -155,6 +165,45 @@ def check_answer(current, input, target)
       end
     end
 
+    # deletes the target from the current data structure
+    def deep_delete(current, target)
+      return current unless current.is_a? Enumerable
+      current.
+          reject  {|value| value == target}.
+          map     {|value| deep_delete(value, target)}
+    end
+
+    # creates an array of values for which any given answer should fail
+    def tests(current, target)
+      [ nil,
+        Array.new,
+        Hash.new,
+        RandomDataStructure.new.generate,
+        deep_delete(current, target)
+      ]
+    end
+
+    # test user input against various tests, for each of which the
+    # input should fail. Returns true only if the user input fails
+    # each of the tests.
+    def test_answer(current, input, target)
+      tests(current, target).all? do |test|
+        !run_test(test, input, target)
+      end
+    end
+
+    # test whether the answer provided by the given 
+    # routine matches the target answer
+    def run_test(current, input, target)
+      routine = lambda { eval(input) }
+      begin
+        output = routine.call
+        output == target
+      rescue Exception
+        false
+      end
+    end
+
     def generate_data_structure
       rds = RandomDataStructure.new
       current = rds.generate
@@ -175,8 +224,12 @@ def play_round # new, exit or check if right/wrong
           return
         else
           if check_answer(current, input, target)
-            itsright
-            correct = true
+            if !test_answer(current, input, target)
+              cheater
+            else
+              itsright
+              correct = true
+            end
           else
             itswrong(target)
           end