macro like "my" in Perl

[Paul Jarc]

I'm looking for something like Perl's "my": something that adds a
binding to the current environment (like internal defines), gives an
error for multiple uses of the same symbol in a single scope (like
internal defines and let), and lets previously-defined variables be
used in values for later bindings (like let*).  I expect I'll have to
wrap the whole scope with a special macro, but I'd like to avoid
having each definition wrap everything that comes after it.  Is there
anything like this already out there?
(new-scope
  (my-define foo #t)
  (do-random-stuff-with foo)
  (my-define bar foo)
  (do-other-stuff-with bar))


paul