#ifndef METAL_LAMBDA_IS_INVOCABLE_HPP
#define METAL_LAMBDA_IS_INVOCABLE_HPP

#include "../config.hpp"
#include "../detail/sfinae.hpp"
#include "../lambda/invoke.hpp"
#include "../value/same.hpp"

#include <type_traits>

namespace metal {
/// \ingroup lambda
///
/// ### Description
/// Checks whether a \lambda is [invocable](\ref invoke) with some \values.
///
/// ### Usage
/// For any \lambda `lbd` and \values `val_0, ..., val_n-1`
/// \code
///     using result = metal::is_invocable<lbd, val_0, ..., val_n-1>;
/// \endcode
///
/// \returns: \number
/// \semantics:
///     If `lbd` holds \expression `expr`, and `expr<val_0, ..., val_n-1>`
///     is well defined after template substitution, then
///     \code
///         using result = metal::true_;
///     \endcode
///     otherwise
///     \code
///         using result = metal::false_;
///     \endcode
///
/// ### Example
/// \snippet lambda.cpp is_invocable
///
/// ### See Also
/// \see lambda, invoke
template <class lbd, class... vals>
using is_invocable = same<std::false_type, typename std::is_base_of<value<>, detail::caller<invoke, lbd, vals...>>::type>;
}

#endif