I think that there should be a Hash#+ method, aking to Array#+.

array = [ "Daniel" ]
array + [ "Carrera" ]  # -> [ "Daniel", "Carrera" ]

hash = { "first" => "Daniel" }
hash + { "last" => "Carrera" } # -> {"first" => "Daniel", 
                               #     "last" => "Carrera"  }

Ditto for Hash#-.

-- 
Daniel Carrera
Graduate Teaching Assistant.  Math Dept.
University of Maryland.  (301) 405-5137