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Investigation: slightly improved similar solution

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This commit is contained in:
Fischlurch 2017-09-27 00:58:12 +02:00
parent 23cc0597b5
commit 3ad3f11f1e
2 changed files with 20 additions and 38 deletions
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50
research/try.cpp
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@ -86,51 +86,25 @@ fun2 (int const& i, int const& j, int const& k)
}
/** Hold a sequence of index numbers as template parameters */
template<size_t...idx>
struct IndexSeq
{
template<size_t i>
using AppendElm = IndexSeq<idx..., i>;
};
/** build an `IndexSeq<0, 1, 2, ..., n-1>` */
template<size_t n>
struct BuildIndexSeq
{
using Ascending = typename BuildIndexSeq<n-1>::Ascending::template AppendElm<n-1>;
template<size_t i>
using FilledWith = typename BuildIndexSeq<n-1>::template FilledWith<i>::template AppendElm<i>;
};
template<>
struct BuildIndexSeq<0>
{
using Ascending = IndexSeq<>;
template<size_t>
using FilledWith = IndexSeq<>;;
};
using lib::meta::IndexSeq;
using lib::meta::BuildIndexSeq;
template<size_t i, typename...ARGS>
struct Pick;
template<size_t i, typename ARG, typename...ARGS>
struct Pick<i, ARG,ARGS...>
: Pick<i-1, ARGS...>
template<size_t i>
struct Pick
{
template<typename ARG, typename...ARGS>
static auto
get (ARG, ARGS ...args)
{
return Pick<i-1, ARGS...>::get (args...);
return Pick<i-1>::get (args...);
}
};
template<typename ARG, typename...ARGS>
struct Pick<0, ARG,ARGS...>
template<>
struct Pick<0>
{
template<typename ARG, typename...ARGS>
static ARG
get (ARG a, ARGS...)
{
@ -143,7 +117,7 @@ void
dispatch_ (IndexSeq<idx...>, ARGS...args)
{
fun1 (Pick<idx,ARGS...>::get(args...) ...);
fun2 (Pick<idx>::get(args...) ...);
}
template<typename...ARGS>
@ -153,8 +127,10 @@ dispatch (ARGS...args)
enum {SIZ = sizeof...(args)};
using First = typename BuildIndexSeq<3>::Ascending;
using Next = typename BuildIndexSeq<3>::OffsetBy<3>;
dispatch_ (First{}, args...);
dispatch_ (First(), args...);
dispatch_ (Next(), args...);
}

8
src/lib/meta/tuple-helper.hpp
View file

@ -214,6 +214,9 @@ namespace meta {
{
using Ascending = typename BuildIndexSeq<n-1>::Ascending::template AppendElm<n-1>;
template<size_t d>
using OffsetBy = typename BuildIndexSeq<n-1>::template OffsetBy<d>::template AppendElm<n-1+d>;
template<size_t i>
using FilledWith = typename BuildIndexSeq<n-1>::template FilledWith<i>::template AppendElm<i>;
};
@ -223,8 +226,11 @@ namespace meta {
{
using Ascending = IndexSeq<>;
template<size_t d>
using OffsetBy = IndexSeq<>;
template<size_t>
using FilledWith = IndexSeq<>;;
using FilledWith = IndexSeq<>;
};