This is the C++ template metaprogramming equivalent of Haskell's State monad. Monadic values are metafunctions classes taking the state as argument and returning (value, state) pairs. The purpose of this monad is to combine such functions.
<mpllibs/metamonad/state.hpp>state_tagreturn's logic: construct a constant function, returning always return's argument regardless of the state and leaving the state unchangedbind's logic: construct a function that gets a value and a new state by passing the state to bind's first argument (which is a function mapping state to a (value, state) pair). The resulting value is passed to bind's second argument as input to construct a new monadic value (a new function expecting a state). This new monadic value is the result of bind.Copyright Abel Sinkovics (abel at elte dot hu) 2011. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt