Equivalent to fold_left; provided for convenience.fold is equivalent to fold_left. However, it is not tag-dispatched on its own because it is just an alias to fold_left. Also note that fold can be called with or without an initial state, just like fold_left: More...
Louis Dionne 2013-2016 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
