| /////////////////////////////////////////////////////////////////////////////// |
| // calculator.hpp |
| // |
| // Copyright 2008 Eric Niebler. 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/proto/core.hpp> |
| #include <boost/proto/context.hpp> |
| #include <boost/test/unit_test.hpp> |
| |
| using namespace boost; |
| |
| struct placeholder {}; |
| proto::terminal<placeholder>::type const _1 = {{}}; |
| |
| struct calculator : proto::callable_context<calculator const> |
| { |
| typedef int result_type; |
| |
| calculator(int i) |
| : i_(i) |
| {} |
| |
| int operator ()(proto::tag::terminal, placeholder) const |
| { |
| return this->i_; |
| } |
| |
| int operator ()(proto::tag::terminal, int j) const |
| { |
| return j; |
| } |
| |
| template<typename Left, typename Right> |
| int operator ()(proto::tag::plus, Left const &left, Right const &right) const |
| { |
| return proto::eval(left, *this) + proto::eval(right, *this); |
| } |
| |
| template<typename Left, typename Right> |
| int operator ()(proto::tag::minus, Left const &left, Right const &right) const |
| { |
| return proto::eval(left, *this) - proto::eval(right, *this); |
| } |
| |
| template<typename Left, typename Right> |
| int operator ()(proto::tag::multiplies, Left const &left, Right const &right) const |
| { |
| return proto::eval(left, *this) * proto::eval(right, *this); |
| } |
| |
| template<typename Left, typename Right> |
| int operator ()(proto::tag::divides, Left const &left, Right const &right) const |
| { |
| return proto::eval(left, *this) / proto::eval(right, *this); |
| } |
| |
| private: |
| int i_; |
| }; |
| |
| template<typename Fun, typename Expr> |
| struct functional |
| { |
| typedef typename proto::result_of::eval<Expr, Fun>::type result_type; |
| |
| functional(Expr const &expr) |
| : expr_(expr) |
| {} |
| |
| template<typename T> |
| result_type operator ()(T const &t) const |
| { |
| Fun fun(t); |
| return proto::eval(this->expr_, fun); |
| } |
| |
| private: |
| Expr const &expr_; |
| }; |
| |
| template<typename Fun, typename Expr> |
| functional<Fun, Expr> as(Expr const &expr) |
| { |
| return functional<Fun, Expr>(expr); |
| } |
| |
| void test_calculator() |
| { |
| BOOST_CHECK_EQUAL(10, proto::eval(((_1 + 42)-3)/4, calculator(1))); |
| BOOST_CHECK_EQUAL(11, proto::eval(((_1 + 42)-3)/4, calculator(5))); |
| |
| BOOST_CHECK_EQUAL(10, as<calculator>(((_1 + 42)-3)/4)(1)); |
| BOOST_CHECK_EQUAL(11, as<calculator>(((_1 + 42)-3)/4)(5)); |
| } |
| |
| using namespace unit_test; |
| /////////////////////////////////////////////////////////////////////////////// |
| // init_unit_test_suite |
| // |
| test_suite* init_unit_test_suite( int argc, char* argv[] ) |
| { |
| test_suite *test = BOOST_TEST_SUITE("test immediate evaluation of proto parse trees"); |
| |
| test->add(BOOST_TEST_CASE(&test_calculator)); |
| |
| return test; |
| } |