anchor.diff:  annotate_return_value(Exprs, Bindings) ->
     [LastExpr|Rest] = lists:reverse(Exprs),
     Line = element(2, LastExpr),
  -  LastExpr2 = #match{line=Line, left=?return_value_var, right=LastExpr},
  +  LastExpr2 = #match{line=Line, left=?return_value_var(Line), right=LastExpr},
     ReturnValue = return_value(output_bindings(Exprs, Bindings), Line),
     lists:reverse([ReturnValue, LastExpr2 | Rest]).
   
  
positive.code: 
  % Generate the return value for eval, appending the binding nodes
  return_value(Bindings, Line) ->
    #tuple{line=Line, elements = [?return_value_var, bindings_list(Bindings, Line)]}.
  
  % Construct the output list for the bindings
  bindings_list([], Line) ->
  
negative.code: -export([new_binding/0, string/1, string/2, exprs/2]).
  -include("../compiler/reia_nodes.hrl").
  -include("../compiler/reia_bindings.hrl").
  -define(return_value_var(Line), #identifier{line=Line, name='__reia_eval_return_value'}).
  
  % Create a new local variable binding
  new_binding() -> [].
  