add FunctionCall instruction and the missing puts (stub)

lib/virtual/block.rb

@@ -34,7 +34,7 @@ module Virtual
     end
 
     # replace a code with an array of new codes. This is what happens in passes all the time
-    def replace_with code , new_codes
+    def replace code , new_codes
       index = @codes.index code
       raise "Code not found #{code} in #{self}" unless index
       @codes.delete_at(index)

lib/virtual/instruction.rb

@@ -75,6 +75,13 @@ module Virtual
     attr_reader :name , :me ,  :args
   end
 
+  class FunctionCall < Instruction
+    def initialize method
+      @method = method
+    end
+    attr_reader :method
+  end
+
   # class for Set instructions, A set is basically a mem move.
   # to and from are indexes into the known objects(frame,message,self and new_message), or from may be a constant
   class Set < Instruction