1 // { dg-options "-std=c++0x" }
2 
3 struct int_placeholder;
4 
5 template<typename T>
6 struct do_replace
7 {
8   typedef T type;
9 };
10 
11 template<>
12 struct do_replace<int_placeholder>
13 {
14   typedef int type;
15 };
16 
17 template<typename T> struct lambdalike
18 {
19   typedef T type;
20 };
21 
22 template<template<typename...> class TT, typename... Args>
23 struct lambdalike<TT<Args...> > {
24   typedef TT<typename do_replace<Args>::type...> type;
25 };
26 
27 
28 template<typename T, typename U>
29 struct is_same
30 {
31   static const bool value = false;
32 };
33 
34 template<typename T>
35 struct is_same<T, T>
36 {
37   static const bool value = true;
38 };
39 
40 template<typename... Elements> struct tuple;
41 template<typename T1, typename T2> struct pair;
42 
43 static_assert(is_same<lambdalike<tuple<float, int_placeholder, double>>::type,
44 		      tuple<float, int, double>>::value,
45 	      "MPL lambda-like replacement on tuple");
46 static_assert(is_same<lambdalike<pair<float, int_placeholder>>::type,
47 		      pair<float, int>>::value,
48 	      "MPL lambda-like replacement on pair");
49 
50 
51 struct _1 {};
52 
53 template<typename Arg0, typename Lambda>
54 struct eval
55 {
56     typedef Lambda type;
57 };
58 
59 template<typename Arg0>
60 struct eval<Arg0, _1>
61 {
62     typedef Arg0 type;
63 };
64 
65 template<typename Arg0, template<typename...> class T, typename... Pack>
66 struct eval<Arg0, T<Pack...> >
67 {
68     typedef T< typename eval<Arg0, Pack>::type... > type;
69 };
70 
71 static_assert(is_same<eval<int, tuple<float, _1, double>>::type,
72 	              tuple<float, int, double>>::value, "eval tuple");
73 static_assert(is_same<eval<int, pair<_1, double>>::type,
74 	              pair<int, double>>::value, "eval pair");
75 static_assert(is_same<eval<int,
76 	                   tuple<pair<_1, _1>, pair<float, float>,
77  	                         pair<double, _1>>>::type,
78 	      tuple<pair<int, int>, pair<float, float>, pair<double, int>>>::value,
79 	      "recursive eval");
80