110 lines
2.8 KiB
C++
Executable File
110 lines
2.8 KiB
C++
Executable File
///////////////////////////////////////////////////////////////////////////////
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// calculator.hpp
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//
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// Copyright 2008 Eric Niebler. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/proto/core.hpp>
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#include <boost/proto/context.hpp>
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#include <boost/test/unit_test.hpp>
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using namespace boost;
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struct placeholder {};
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proto::terminal<placeholder>::type const _1 = {{}};
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struct calculator : proto::callable_context<calculator const>
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{
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typedef int result_type;
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calculator(int i)
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: i_(i)
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{}
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int operator ()(proto::tag::terminal, placeholder) const
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{
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return this->i_;
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}
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int operator ()(proto::tag::terminal, int j) const
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{
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return j;
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}
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template<typename Left, typename Right>
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int operator ()(proto::tag::plus, Left const &left, Right const &right) const
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{
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return proto::eval(left, *this) + proto::eval(right, *this);
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}
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template<typename Left, typename Right>
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int operator ()(proto::tag::minus, Left const &left, Right const &right) const
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{
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return proto::eval(left, *this) - proto::eval(right, *this);
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}
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template<typename Left, typename Right>
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int operator ()(proto::tag::multiplies, Left const &left, Right const &right) const
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{
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return proto::eval(left, *this) * proto::eval(right, *this);
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}
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template<typename Left, typename Right>
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int operator ()(proto::tag::divides, Left const &left, Right const &right) const
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{
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return proto::eval(left, *this) / proto::eval(right, *this);
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}
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private:
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int i_;
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};
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template<typename Fun, typename Expr>
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struct functional
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{
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typedef typename proto::result_of::eval<Expr, Fun>::type result_type;
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functional(Expr const &expr)
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: expr_(expr)
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{}
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template<typename T>
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result_type operator ()(T const &t) const
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{
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Fun fun(t);
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return proto::eval(this->expr_, fun);
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}
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private:
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Expr const &expr_;
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};
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template<typename Fun, typename Expr>
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functional<Fun, Expr> as(Expr const &expr)
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{
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return functional<Fun, Expr>(expr);
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}
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void test_calculator()
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{
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BOOST_CHECK_EQUAL(10, proto::eval(((_1 + 42)-3)/4, calculator(1)));
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BOOST_CHECK_EQUAL(11, proto::eval(((_1 + 42)-3)/4, calculator(5)));
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BOOST_CHECK_EQUAL(10, as<calculator>(((_1 + 42)-3)/4)(1));
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BOOST_CHECK_EQUAL(11, as<calculator>(((_1 + 42)-3)/4)(5));
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}
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using namespace unit_test;
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///////////////////////////////////////////////////////////////////////////////
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// init_unit_test_suite
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//
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test_suite* init_unit_test_suite( int argc, char* argv[] )
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{
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test_suite *test = BOOST_TEST_SUITE("test immediate evaluation of proto parse trees");
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test->add(BOOST_TEST_CASE(&test_calculator));
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return test;
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}
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