FM / hof

/usr/include/boost/hof

Name	Size	Mode	Actions
detail/	-	0755	rm
alias.hpp	5552	0644	edit dl rm
always.hpp	4261	0644	edit dl rm
apply.hpp	8363	0644	edit dl rm
apply_eval.hpp	4428	0644	edit dl rm
arg.hpp	3148	0644	edit dl rm
capture.hpp	5419	0644	edit dl rm
combine.hpp	3877	0644	edit dl rm
compose.hpp	5042	0644	edit dl rm
config.hpp	6149	0644	edit dl rm
construct.hpp	8774	0644	edit dl rm
decay.hpp	1790	0644	edit dl rm
decorate.hpp	6329	0644	edit dl rm
eval.hpp	2400	0644	edit dl rm
first_of.hpp	7100	0644	edit dl rm
fix.hpp	6314	0644	edit dl rm
flip.hpp	2690	0644	edit dl rm
flow.hpp	5060	0644	edit dl rm
fold.hpp	5000	0644	edit dl rm
function.hpp	3129	0644	edit dl rm
function_param_limit.hpp	1658	0644	edit dl rm
identity.hpp	1884	0644	edit dl rm
if.hpp	3314	0644	edit dl rm
implicit.hpp	4041	0644	edit dl rm
indirect.hpp	3268	0644	edit dl rm
infix.hpp	6043	0644	edit dl rm
is_invocable.hpp	1706	0644	edit dl rm
is_unpackable.hpp	3341	0644	edit dl rm
lambda.hpp	6458	0644	edit dl rm
lazy.hpp	8729	0644	edit dl rm
lift.hpp	3752	0644	edit dl rm
limit.hpp	3817	0644	edit dl rm
match.hpp	3331	0644	edit dl rm
mutable.hpp	1988	0644	edit dl rm
pack.hpp	12747	0644	edit dl rm
partial.hpp	8307	0644	edit dl rm
pipable.hpp	6227	0644	edit dl rm
placeholders.hpp	13799	0644	edit dl rm
proj.hpp	7517	0644	edit dl rm
protect.hpp	2145	0644	edit dl rm
repeat.hpp	4184	0644	edit dl rm
repeat_while.hpp	5154	0644	edit dl rm
result.hpp	3644	0644	edit dl rm
returns.hpp	8607	0644	edit dl rm
reveal.hpp	12187	0644	edit dl rm
reverse_fold.hpp	5271	0644	edit dl rm
rotate.hpp	2576	0644	edit dl rm
static.hpp	2395	0644	edit dl rm
tap.hpp	2118	0644	edit dl rm
unpack.hpp	5588	0644	edit dl rm
unpack_sequence.hpp	1810	0644	edit dl rm
version.hpp	679	0644	edit dl rm

Edit: /usr/include/boost/hof/reveal.hpp (12187B)

/*=============================================================================
    Copyright (c) 2014 Paul Fultz II
    reveal.h
    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)
==============================================================================*/

#ifndef BOOST_HOF_GUARD_FUNCTION_REVEAL_H
#define BOOST_HOF_GUARD_FUNCTION_REVEAL_H

/// reveal
/// ======
/// 
/// Description
/// -----------
/// 
/// The `reveal` function adaptor helps shows the error messages that get
/// masked on some compilers. Sometimes an error in a function that causes a
/// substitution failure, will remove the function from valid overloads. On
/// compilers without a backtrace for substitution failure, this will mask the
/// error inside the function. The `reveal` adaptor will expose these error
/// messages while still keeping the function SFINAE-friendly.
/// 
/// Sample
/// ------
/// 
/// If we take the `print` example from the quick start guide like this:
/// 
///     namespace adl {
/// 
///     using std::begin;
/// 
///     template<class R>
///     auto adl_begin(R&& r) BOOST_HOF_RETURNS(begin(r));
///     }
/// 
///     BOOST_HOF_STATIC_LAMBDA_FUNCTION(for_each_tuple) = [](const auto& sequence, auto f) BOOST_HOF_RETURNS
///     (
///         boost::hof::unpack(boost::hof::proj(f))(sequence)
///     );
/// 
///     auto print = boost::hof::fix(boost::hof::first_of(
///         [](auto, const auto& x) -> decltype(std::cout << x, void())
///         {
///             std::cout << x << std::endl;
///         },
///         [](auto self, const auto& range) -> decltype(self(*adl::adl_begin(range)), void())
///         {
///             for(const auto& x:range) self(x);
///         },
///         [](auto self, const auto& tuple) -> decltype(for_each_tuple(tuple, self), void())
///         {
///             return for_each_tuple(tuple, self);
///         }
///     ));
/// 
/// Which prints numbers and vectors:
/// 
///     print(5);
/// 
///     std::vector<int> v = { 1, 2, 3, 4 };
///     print(v);
/// 
/// However, if we pass a type that can't be printed, we get an error like
/// this:
/// 
///     print.cpp:49:5: error: no matching function for call to object of type 'boost::hof::fix_adaptor<boost::hof::first_of_adaptor<(lambda at print.cpp:29:9), (lambda at print.cpp:33:9), (lambda at print.cpp:37:9)> >'
///         print(foo{});
///         ^~~~~
///     fix.hpp:158:5: note: candidate template ignored: substitution failure [with Ts = <foo>]: no matching function for call to object of type 'const boost::hof::first_of_adaptor<(lambda at
///           print.cpp:29:9), (lambda at print.cpp:33:9), (lambda at print.cpp:37:9)>'
///         operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
/// 
/// Which is short and gives very little information why it can't be called.
/// It doesn't even show the overloads that were try. However, using the
/// `reveal` adaptor we can get more info about the error like this:
/// 
///     print.cpp:49:5: error: no matching function for call to object of type 'boost::hof::reveal_adaptor<boost::hof::fix_adaptor<boost::hof::first_of_adaptor<(lambda at print.cpp:29:9), (lambda at print.cpp:33:9),
///           (lambda at print.cpp:37:9)> >, boost::hof::fix_adaptor<boost::hof::first_of_adaptor<(lambda at print.cpp:29:9), (lambda at print.cpp:33:9), (lambda at print.cpp:37:9)> > >'
///         boost::hof::reveal(print)(foo{});
///         ^~~~~~~~~~~~~~~~~~
///     reveal.hpp:149:20: note: candidate template ignored: substitution failure [with Ts = <foo>, $1 = void]: no matching function for call to object of type '(lambda at print.cpp:29:9)'
///         constexpr auto operator()(Ts&&... xs) const
///                        ^
///     reveal.hpp:149:20: note: candidate template ignored: substitution failure [with Ts = <foo>, $1 = void]: no matching function for call to object of type '(lambda at print.cpp:33:9)'
///         constexpr auto operator()(Ts&&... xs) const
///                        ^
///     reveal.hpp:149:20: note: candidate template ignored: substitution failure [with Ts = <foo>, $1 = void]: no matching function for call to object of type '(lambda at print.cpp:37:9)'
///         constexpr auto operator()(Ts&&... xs) const
///                        ^
///     fix.hpp:158:5: note: candidate template ignored: substitution failure [with Ts = <foo>]: no matching function for call to object of type 'const boost::hof::first_of_adaptor<(lambda at
///           print.cpp:29:9), (lambda at print.cpp:33:9), (lambda at print.cpp:37:9)>'
///         operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
/// 
/// So now the error has a note for each of the lambda overloads it tried. Of
/// course this can be improved even further by providing custom reporting of
/// failures.
/// 
/// Synopsis
/// --------
/// 
///     template<class F>
///     reveal_adaptor<F> reveal(F f);
/// 
/// Requirements
/// ------------
/// 
/// F must be:
/// 
/// * [ConstInvocable](ConstInvocable)
/// * MoveConstructible
/// 
/// Reporting Failures
/// ------------------
/// 
/// By default, `reveal` reports the substitution failure by trying to call
/// the function. However, more detail expressions can be be reported from a
/// template alias by using `as_failure`. This is done by defining a nested
/// `failure` struct in the function object and then inheriting from
/// `as_failure`. Also multiple failures can be reported by using
/// `with_failures`.
/// 
/// Synopsis
/// --------
/// 
///     // Report failure by instantiating the Template
///     template<template<class...> class Template>
///     struct as_failure;
/// 
///     // Report multiple falures
///     template<class... Failures>
///     struct with_failures;
/// 
///     // Report the failure for each function
///     template<class... Fs>
///     struct failure_for;
/// 
///     // Get the failure of a function
///     template<class F>
///     struct get_failure;
/// 
/// Example
/// -------
/// 
///     #include <boost/hof.hpp>
///     #include <cassert>
/// 
///     struct sum_f
///     {
///         template<class T, class U>
///         using sum_failure = decltype(std::declval<T>()+std::declval<U>());
/// 
///         struct failure
///         : boost::hof::as_failure<sum_failure>
///         {};
/// 
///         template<class T, class U>
///         auto operator()(T x, U y) const BOOST_HOF_RETURNS(x+y);
///     };
/// 
///     int main() {
///         assert(sum_f()(1, 2) == 3);
///     }
///

#include <boost/hof/always.hpp>
#include <boost/hof/returns.hpp>
#include <boost/hof/is_invocable.hpp>
#include <boost/hof/identity.hpp>
#include <boost/hof/detail/move.hpp>
#include <boost/hof/detail/callable_base.hpp>
#include <boost/hof/detail/delegate.hpp>
#include <boost/hof/detail/holder.hpp>
#include <boost/hof/detail/join.hpp>
#include <boost/hof/detail/make.hpp>
#include <boost/hof/detail/static_const_var.hpp>
#include <boost/hof/detail/using.hpp>

#ifndef BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS
#ifdef __clang__
#define BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS 1
#else
#define BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS 0
#endif
#endif

namespace boost { namespace hof {

namespace detail {

template<class T, class=void>
struct has_failure
: std::false_type
{};

template<class T>
struct has_failure<T, typename holder<
    typename T::failure
>::type>
: std::true_type
{};

struct identity_failure
{
    template<class T>
    T operator()(T&& x);

template<class T>
    static T&& val();
#if BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS
    template<template<class...> class Template, class... Ts>
    BOOST_HOF_USING(defer, Template<Ts...>);
#else
    template<template<class...> class Template, class... Ts>
    static auto defer(Ts&&...) -> Template<Ts...>;
#endif

};

}

template<class F, class=void>
struct get_failure
{
    template<class... Ts>
    struct of
    {
#if BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS
        template<class Id>
        using apply = decltype(Id()(std::declval<F>())(std::declval<Ts>()...));
#else
        template<class Id>
        static auto apply(Id id) -> decltype(id(std::declval<F>())(std::declval<Ts>()...));
#endif
    };
};

template<class F>
struct get_failure<F, typename std::enable_if<detail::has_failure<F>::value>::type>
: F::failure
{};

template<template<class...> class Template>
struct as_failure
{
    template<class... Ts>
    struct of
    {
#if BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS
        template<class Id>
        using apply = typename Id::template defer<Template, Ts...>;
#else
        template<class Id>
        static auto apply(Id) -> decltype(Id::template defer<Template, Ts...>());
#endif
    };
};

namespace detail {
template<class Failure, class... Ts>
BOOST_HOF_USING_TYPENAME(apply_failure, Failure::template of<Ts...>);

template<class F, class Failure>
struct reveal_failure
{
    // Add default constructor to make clang 3.4 happy
    constexpr reveal_failure()
    {}
    // This is just a placeholder to produce a note in the compiler, it is
    // never called
    template<
        class... Ts, 
        class=typename std::enable_if<(!is_invocable<F, Ts...>::value)>::type
    >
    constexpr auto operator()(Ts&&... xs) const
#if BOOST_HOF_REVEAL_USE_TEMPLATE_ALIAS
        -> typename apply_failure<Failure, Ts...>::template apply<boost::hof::detail::identity_failure>;
#else
        -> decltype(apply_failure<Failure, Ts...>::apply(boost::hof::detail::identity_failure()));
#endif
};

template<class F, class Failure=get_failure<F>, class=void>
struct traverse_failure 
: reveal_failure<F, Failure>
{
    constexpr traverse_failure()
    {}
};

template<class F, class Failure>
struct traverse_failure<F, Failure, typename holder< 
    typename Failure::children
>::type> 
: Failure::children::template overloads<F>
{
    constexpr traverse_failure()
    {}
};

template<class Failure, class Transform, class=void>
struct transform_failures 
: Transform::template apply<Failure>
{};

template<class Failure, class Transform>
struct transform_failures<Failure, Transform, typename holder< 
    typename Failure::children
>::type> 
: Failure::children::template transform<Transform>
{};

}

template<class Failure, class... Failures>
struct failures;

template<class... Fs>
struct with_failures
{
    typedef BOOST_HOF_JOIN(failures, Fs...) children;
};

template<class Failure, class... Failures>
struct failures 
{
    template<class Transform>
    BOOST_HOF_USING(transform, with_failures<detail::transform_failures<Failure, Transform>, detail::transform_failures<Failures, Transform>...>);

template<class F, class FailureBase=BOOST_HOF_JOIN(failures, Failures...)>
    struct overloads
    : detail::traverse_failure<F, Failure>, FailureBase::template overloads<F>
    {
        constexpr overloads()
        {}
        using detail::traverse_failure<F, Failure>::operator();
        using FailureBase::template overloads<F>::operator();
    };
};

template<class Failure>
struct failures<Failure>
{
    template<class Transform>
    BOOST_HOF_USING(transform, with_failures<detail::transform_failures<Failure, Transform>>);

template<class F>
    BOOST_HOF_USING(overloads, detail::traverse_failure<F, Failure>);
};

template<class Transform, class... Fs>
struct failure_map
: with_failures<detail::transform_failures<get_failure<Fs>, Transform>...>
{};

template<class... Fs>
struct failure_for
: with_failures<get_failure<Fs>...>
{};

template<class F, class Base=detail::callable_base<F>>
struct reveal_adaptor
: detail::traverse_failure<Base>, Base
{
    typedef reveal_adaptor fit_rewritable1_tag;
    using detail::traverse_failure<Base>::operator();
    using Base::operator();

BOOST_HOF_INHERIT_CONSTRUCTOR(reveal_adaptor, Base);
};
// Avoid double reveals, it causes problem on gcc 4.6
template<class F>
struct reveal_adaptor<reveal_adaptor<F>>
: reveal_adaptor<F>
{
    typedef reveal_adaptor fit_rewritable1_tag;
    BOOST_HOF_INHERIT_CONSTRUCTOR(reveal_adaptor, reveal_adaptor<F>);
};

BOOST_HOF_DECLARE_STATIC_VAR(reveal, detail::make<reveal_adaptor>);

}} // namespace boost::hof

#endif

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