I did something like this:

  foo = File::SEPARATOR
  foo << "foo"

  bar = File::SEPARATOR
  bar << "bar"

  p foo, bar

And I got this:

  "/foobar"
  "/foobar"

This is not what I expected, but it makes sense, because I am modifing
File::SEPARATOR.  Would it make sense to freeze File::SEPARATOR to keep
this from happening?  With what other "constants" might this problem
occur?

Paul