BOOST_VMD_IS_SEQ — Determines if a sequence is a Boost PP seq.
// In header: <boost/vmd/is_seq.hpp> BOOST_VMD_IS_SEQ(sequence)
The macro checks that the sequence is a Boost PP seq. It returns 1 if it is a seq, else if returns 0.
sequence = a possible Boost PP seq
returns = 1 if it a seq, else returns 0.
A single set of parentheses, with a single element, is parsed as a tuple and not a seq. To be parsed as a seq the input needs to be more than one consecutive sets of parentheses, each with a single element of data.