#ifndef METAL_LAMBDA_LAZY_HPP
#define METAL_LAMBDA_LAZY_HPP

#include "../config.hpp"
#include "../lambda/bind.hpp"
#include "../lambda/lambda.hpp"
#include "../value/eval.hpp"

namespace metal {
/// \ingroup lambda
///
/// ### Description
/// Constructs a \lambda out of a _lazy expression_, that is, an
/// \expression whose return \value is defined as a nested typename `type`.
///
/// ### Usage
/// For any \expression `expr`
/// \code
///     using result = metal::lazy<expr>;
/// \endcode
///
/// \returns: \lambda
/// \semantics:
///     Equivalent to
///     \code
///         using result = metal::lambda<eager>;
///     \endcode
///     where `eager` is an \expression such that
///     \code
///         template<class... args>
///         using eager = typename expr<args...>::type;
///     \endcode
///
/// ### Example
/// \snippet lambda.cpp lazy
///
/// ### See Also
/// \see lambda, eval
template <template <class...> class expr>
using lazy = metal::bind<metal::lambda<metal::eval>, metal::lambda<expr>>;
}

#endif