A tuple is a simple comma-separated list of elements inside
parenthesis. For example,
(a, b, c)
...is a tuple of 3 elements--a, b, and
Tuples are fast and easy to use. With variadic macro
support it is not necessary to know the size of a tuple; without
variadic macro support all access to tuples requires
knowledge of its size. Use a tuple instead of an array if
your compiler supports variadic macros, since a tuple has all of
the functionality as an array and is easier syntactically to use.
Elements of a tuple can be extracted with BOOST_PP_TUPLE_ELEM.