1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
// { dg-options "-std=c++0x" }
struct int_placeholder;
template<typename T>
struct do_replace
{
typedef T type;
};
template<>
struct do_replace<int_placeholder>
{
typedef int type;
};
template<typename T> struct lambdalike
{
typedef T type;
};
template<template<typename...> class TT, typename... Args>
struct lambdalike<TT<Args...> > {
typedef TT<typename do_replace<Args>::type...> type;
};
template<typename T, typename U>
struct is_same
{
static const bool value = false;
};
template<typename T>
struct is_same<T, T>
{
static const bool value = true;
};
template<typename... Elements> struct tuple;
template<typename T1, typename T2> struct pair;
static_assert(is_same<lambdalike<tuple<float, int_placeholder, double>>::type,
tuple<float, int, double>>::value,
"MPL lambda-like replacement on tuple");
static_assert(is_same<lambdalike<pair<float, int_placeholder>>::type,
pair<float, int>>::value,
"MPL lambda-like replacement on pair");
struct _1 {};
template<typename Arg0, typename Lambda>
struct eval
{
typedef Lambda type;
};
template<typename Arg0>
struct eval<Arg0, _1>
{
typedef Arg0 type;
};
template<typename Arg0, template<typename...> class T, typename... Pack>
struct eval<Arg0, T<Pack...> >
{
typedef T< typename eval<Arg0, Pack>::type... > type;
};
static_assert(is_same<eval<int, tuple<float, _1, double>>::type,
tuple<float, int, double>>::value, "eval tuple");
static_assert(is_same<eval<int, pair<_1, double>>::type,
pair<int, double>>::value, "eval pair");
static_assert(is_same<eval<int,
tuple<pair<_1, _1>, pair<float, float>,
pair<double, _1>>>::type,
tuple<pair<int, int>, pair<float, float>, pair<double, int>>>::value,
"recursive eval");
|
