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///////////////////////////////////////////////////////////////////////////////
// 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;
}
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