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lazy default value evaluation

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[SVN r1874]
This commit is contained in:
Daniel Wallin
2004-01-14 21:22:50 +00:00
parent 9fbc78d669
commit 1fd53b1465
1 changed files with 40 additions and 6 deletions
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46
test/named_params_test.cpp
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@@ -7,6 +7,14 @@
#include <boost/type_traits/is_convertible.hpp>
#include <cassert>
#include <string.h>
//#include <iostream>
#include <boost/ref.hpp>
/*
BOOST_NAMED_PARAMS_FUN(int, f, 0, 3, f_keywords)
{
return p[index];
}
*/
namespace test
{
@@ -32,21 +40,44 @@ namespace test
struct tester_t;
keyword<tester_t> tester;
struct X
{
X(const char*) {}
};
template<class T>
struct convertible_from
{
template<class U>
struct apply : boost::is_convertible<U, T>
{};
};
struct f_keywords // vc6 is happier with inheritance than with a typedef
: keywords<
tester_t
, arg<name_t, boost::mpl::false_, boost::is_convertible<boost::mpl::_1, const char*> >
, arg<name_t, boost::mpl::false_, convertible_from<const char*> >
, value_t
, index_t
>
{};
struct value_default
{
typedef double result_type;
double operator()() const
{
return 666.222;
}
};
template<class Params>
int f_impl(const Params& p)
{
{
p[tester](
p[name]
, p[value | 666.222]
, p[value || value_default() ]
, p[index | 999]
);
return 1;
@@ -90,10 +121,14 @@ namespace test
values_t(Name const& n, Value const& v, Index const& i)
: n(n), v(v), i(i)
{}
template <class Name_, class Value_, class Index_>
void operator()(Name_ const& n_, Value_ const& v_, Index_ const& i_) const
{
/* std::cout << typeid(Name_).name() << "\n";
std::cout << typeid(Value_).name() << "\n";
std::cout << typeid(Index_).name() << "\n";
*/
// vc7 fails on these assert because of constness mismatch
// BOOST_STATIC_ASSERT((boost::is_same<Name,Name_>::value));
assert(equal(n, n_));
@@ -116,7 +151,6 @@ namespace test
}
}
struct Foo { operator const char*() const { return "foo"; } };
int main()
{
using test::f;
@@ -132,7 +166,7 @@ int main()
f(
test::values("foo", 666.222, 56)
, index = 56, name = "foo"
, index = boost::cref(56), name = "foo"
);
//f(index = 56, name = 55); // won't compile