leaf/test/defer_test.0.cpp

//Copyright (c) 2018 Emil Dotchevski
//Copyright (c) 2018 Second Spectrum, Inc.

//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)

#include <boost/leaf/expect.hpp>
#include <boost/leaf/preload.hpp>
#include <boost/detail/lightweight_test.hpp>

namespace leaf = boost::leaf;

int global;

int
get_global() noexcept
	{
	return global;
	}
struct
info
	{
	int value;
	};
leaf::error
g()
	{
	global = 0;
	auto propagate = leaf::defer( [ ] { return info{get_global()}; } );
	global = 42;
	return leaf::error();
	}
leaf::error
f()
	{
	return g();
	}
int
main()
	{
	leaf::expect<info> exp;
	int c=0;
	BOOST_TEST( handle_error( exp, f(),
		leaf::match<info>( [&c]( int i42 )
			{
			BOOST_TEST(i42==42);
			++c;
			} ) ) );
	BOOST_TEST(c==1);
	return boost::report_errors();
	}