[section Header Organization]

The main header you will always need to use _yap_ is the _alg_header_.  If you
want to ensure that you don't accidentally use _expr_ (which I recommend),
just include this header and nothing else.

If you want to use the _expr_ reference expression template (great for
prototyping, but not recommended for production work), include the
_expr_header_.

If you want to include all of the above, use the _yap_header_.

If you want to use _print_, include the _print_header_; this header is not
included in the _yap_header_.

[endsect]