rename Mystery

just unknown, mystery should be more difficult to find out.
After all we keep run time info, so just need unknown at compile time

lib/virtual/compiled_method_info.rb

@@ -43,7 +43,7 @@ module Virtual
       method.info = CompiledMethodInfo.new
       method
     end
-    def initialize return_type = Virtual::Mystery
+    def initialize return_type = Virtual::Unknown
       # first block we have to create with .new , as new_block assumes a current
       enter = Block.new( "enter"  , self ).add_code(MethodEnter.new())
       @return_type = return_type

lib/virtual/compiler.rb

@@ -11,7 +11,7 @@ module Virtual
     # Everything in ruby is an expression, ie returns a value. So the effect of every compile
     # is that a value is put into the ReturnSlot of the current Message.
     # The compile method (so every compile method) returns the value that it deposits which
-    # may be unknown Mystery value.
+    # may be unknown Unknown value.
     #
     # The Compiler.compile uses a visitor patter to dispatch according to the class name of
     # the expression. So a NameExpression is delegated to compile_name etc.

lib/virtual/compiler/basic_expressions.rb

@@ -68,6 +68,7 @@ module Virtual
 
   #    attr_reader  :string
       def self.compile_string expression , method
+        # Clearly a TODO here to implement strings rather than reusing symbols
         value = expression.string.to_sym
         to = Return.new(Reference , value)
         method.info.constants << value
@@ -94,7 +95,7 @@ module Virtual
 
       def self.compile_variable expression, method
         method.info.add_code InstanceGet.new(expression.name)
-        Return.new( Mystery )
+        Return.new( Unknown )
       end
   end
 end

lib/virtual/slots/message_slot.rb

@@ -1,26 +1,26 @@
 module Virtual
   # The message that is being processed has a layout as per the constant above
   class MessageSlot < Slot
-    def initialize index , type = Mystery , value = nil
+    def initialize index , type = Unknown , value = nil
       super(index ,type , value )
     end
   end
 
   class Return < MessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_RETURN_VALUE , type , value  )
     end
   end
 
   class Self < MessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_SELF , type , value  )
     end
   end
 
   # Name of the current message
   class Name < MessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_NAME , type , value  )
     end
   end

lib/virtual/slots/new_message_slot.rb

@@ -1,24 +1,24 @@
 module Virtual
   class NewMessageSlot < Slot
-    def initialize index , type = Mystery, value = nil
+    def initialize index , type = Unknown, value = nil
       super(index , type , value )
     end
   end
 
   class NewReturn < NewMessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_RETURN_VALUE, type , value  )
     end
   end
 
   class NewSelf < NewMessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_SELF , type , value  )
     end
   end
 
   class NewName < NewMessageSlot
-    def initialize type = Mystery, value = nil
+    def initialize type = Unknown, value = nil
       super( MESSAGE_NAME, type , value )
     end
   end

lib/virtual/slots/slot.rb

@@ -42,13 +42,13 @@ module Virtual
   end
 
   class FrameSlot < Slot
-    def initialize index , type = Mystery, value = nil
+    def initialize index , type = Unknown, value = nil
       super
     end
   end
 
   class SelfSlot < Slot
-    def initialize index , type = Mystery, value = nil
+    def initialize index , type = Unknown, value = nil
       super
     end
   end

lib/virtual/type.rb

@@ -1,7 +1,7 @@
 
 module Virtual
   # Integer and (Object) References are the main derived classes, but float will come and ...
-  # The Mystery Type has unknown type and has only casting methods. So it must be cast to be useful.
+  # The Unknown Type has unknown type and has only casting methods. So it must be cast to be useful.
   class Type
     def == other
       return false unless other.class == self.class
@@ -20,7 +20,7 @@ module Virtual
     attr_reader :of_class
   end
 
-  class Mystery < Type
+  class Unknown < Type
   end
 
 end