anchor.diff:    ;
   
   element_list :
  -     element (element_separator_list element2)*
  +     element (element_separator_list element)*
     ;
   
   element :
        expr_in_array
  -  ;
  -
  -element2 :
  -     expr_in_array2
     ;
   
   //non-empty
  
positive.code: 
  //TODO-AC: antlr periodically has trouble with this (because of unary plus?)
  plus_expr_in_array :
       binary_expr_in_array (t_FILLER (t_PLUS | t_MINUS) t_FILLER binary_expr_in_array | (t_PLUS | t_MINUS) t_FILLER? binary_expr_in_array)*
    ;
  
  binary_expr_in_array :
  
negative.code:   |  name t_AT name
    ;
  
  //TODO-AC: This is separate from expr because it allows t_COLON and t_END
  //  This shouldn't be necessary - dynamic scopes should handle this.
  //  See revision 709 for an implementation with dynamic scopes.
  