persist LCD too

lib/rpl.rb

@@ -37,7 +37,7 @@ class Rpl < Interpreter
   def persist_state
     return if @persistence_filename.nil?
 
-    File.write(@persistence_filename, "#{export_vars}\n#{export_stack}")
+    File.write(@persistence_filename, "#{export_lcd}\n#{export_vars}\n#{export_stack}")
   end
 
   def run!( input )

lib/rpl/interpreter.rb

@@ -77,6 +77,13 @@ class Interpreter
     args
   end
 
+  def export_lcd
+    lcd_as_string = "@ LCD:\n"
+    lcd_as_string += "#{@lcd_grob} →lcd\n"
+
+    lcd_as_string
+  end
+
   def export_vars
     vars_as_string = "@ variables:\n"
     vars_as_string += @dictionary.vars