If you are encapsulating something that is generally referred to by an
acronym, is it better to use all caps, even though in Ruby that
usually indicates a constant value of some sort other than a class or
module. Or is better to capitalize the term so it conforms to the
typical look of class/module names.

Eg.

  XML::Document  -or-  Xml::Document

  POM::Metadata  -or-  Pom::Metadata

  ANSI::Code     -or-  Ansi::Code

I can't seem to ever make up my mind about this, so I thought I'd ask
and see if there is some sort of general consensus or if someone else
has some sort of concrete basis on which to decide.