yap/test/placeholder_eval.cpp

// Copyright (C) 2016-2018 T. Zachary Laine
//
// 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/yap/expression.hpp>

#include <gtest/gtest.h>

#include <sstream>


template<typename T>
using term = boost::yap::terminal<boost::yap::expression, T>;

template<long long I>
using place_term =
    boost::yap::terminal<boost::yap::expression, boost::yap::placeholder<I>>;

template<typename T>
using ref = boost::yap::expression_ref<boost::yap::expression, T>;

namespace yap = boost::yap;
namespace bh = boost::hana;


TEST(placeholder_eval, test_placeholder_eval)
{
    using namespace boost::yap::literals;

    place_term<3> p3 = 3_p;
    int i_ = 42;
    term<int> i{std::move(i_)};
    yap::expression<
        yap::expr_kind::plus,
        bh::tuple<ref<place_term<3> &>, term<int>>>
        expr = p3 + std::move(i);
    yap::expression<
        yap::expr_kind::plus,
        bh::tuple<
            ref<place_term<3> &>,
            yap::expression<
                yap::expr_kind::plus,
                bh::tuple<ref<place_term<3> &>, term<int>>>>>
        unevaluated_expr = p3 + std::move(expr);

    {
        double result = evaluate(p3, 5, 6, 7);
        EXPECT_EQ(result, 7);
    }

    {
        double result = evaluate(expr, std::string("15"), 3, 1);
        EXPECT_EQ(result, 43);
    }

    {
        double result = evaluate(unevaluated_expr, std::string("15"), 2, 3);
        EXPECT_EQ(result, 48);
    }
}