allow for empty view

and reset view when interpreter restarts

lib/views/blocks_view.rb

@@ -4,7 +4,10 @@ class BlocksView < ListView
   def initialize interpreter
     @interpreter = interpreter
     @interpreter.register_event(:instruction_changed,  self)
-    super([BlockView.new(@interpreter.block)])
+    @interpreter.register_event(:state_changed,  self)
+    show = []
+    show << BlockView.new(@interpreter.block) if @interpreter.block
+    super(show)
     @method_name = method_name
   end
 
@@ -20,12 +23,19 @@ class BlocksView < ListView
       @method_name = new_name
       @element.at_css(".method").text = method_name
     end
-    return if @interpreter.block.object_id == @children.last.block.object_id
+    if @children.last
-    @elements.last.at_css(".bright").remove_class("bright")
+      return if @interpreter.block.object_id == @children.last.block.object_id
+      @elements.last.at_css(".bright").remove_class("bright")
+    end
     append_view( BlockView.new(@interpreter.block) )
     remove_first if( @elements.length > 6)
   end
 
+  def state_changed old , new_s
+    return unless new_s == :running
+    clear_view
+  end
+
   def method_name
     bl = @interpreter.block
     return "" unless bl

lib/views/classes_view.rb

@@ -15,7 +15,7 @@ class ClassesView < ListView
   def draw
     super()
     wrap_element div("ul.nav!")
-    wrap_element( div(".classes") << div("h4" , "Classes") )
+    wrap_element( div("h4" , "Classes") )
     return @element
   end
 

lib/views/instruction_view.rb

@@ -5,8 +5,13 @@ class InstructionView < ListView
 
   def initialize interpreter
     @interpreter = interpreter
-    super([ConstantView.new( "span.bright" , "starting" )])
+    super([start_view])
     @interpreter.register_event(:instruction_changed,  self)
+    @interpreter.register_event(:state_changed,  self)
+  end
+
+  def start_view
+    ConstantView.new( "span.bright" , "starting" )
   end
 
   def instruction_changed
@@ -23,6 +28,12 @@ class InstructionView < ListView
     @element
   end
 
+  def state_changed old , new_s
+    return unless new_s == :running
+    clear_view
+    append_view start_view
+  end
+
   def instruction_text
     return "" unless @interpreter.instruction
     @interpreter.instruction.to_s