lauchmelder/metaprogramming
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lauchmelder 2024-11-27 20:27:51 +01:00
commit 57d43acd16
6 changed files with 180 additions and 0 deletions

2
.gitignore vendored Normal file
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.cache/
compile_commands.json

8
CMakeLists.txt Normal file
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cmake_minimum_required(VERSION 3.20)
project(templates CXX)
set(CMAKE_CXX_STANDARD 20)
add_executable(templates
src/main.cpp
)

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src/Data.hpp Normal file
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#pragma once
#include <cstdint>
template<typename Type, Type Value>
struct Data {
using type = Type;
static constexpr Type value = Value;
};
template<int64_t Value>
struct Number :
public Data<int64_t, Value>
{};

35
src/Lambda.hpp Normal file
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#include "Data.hpp"
template <typename Return, typename... Parameters>
struct Lambda {
using returnType = Return;
// using paramType = Parameter;
};
template <typename X>
struct Identity :
public Lambda<typename X::type, typename X::type>
{
using value = X;
};
template <typename X>
struct NumericIncrement :
public Lambda<typename X::type, typename X::type>
{
using value = Number<X::value + 1>;
};
template <typename X>
struct NumericDouble :
public Lambda<typename X::type, typename X::type>
{
using value = Number<X::value * 2>;
};
template <typename X, typename Y>
struct NumericAdd :
public Lambda<typename X::type, typename X::type, typename Y::type>
{
using value = Number<X::value + Y::value>;
};

75
src/List.hpp Normal file
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#pragma once
#include <cstdint>
#include <type_traits>
#include "Lambda.hpp"
template <typename Head, typename Cons>
struct List {
using type = typename Head::type;
using value = Head;
using cons = Cons;
};
template <>
struct List<void, void> {
using type = void;
using value = void;
};
template <typename Head>
struct List<Head, void> {
using type = typename Head::type;
using value = Head;
using cons = ::List<void, void>;
};
template<typename Head, typename... Cons>
struct ListConstructor {
using value = ::List<Head, typename ListConstructor<Cons...>::value>;
};
template<typename Head>
struct ListConstructor<Head> {
using value = ::List<Head, void>;
};
template<typename List, uint64_t N>
struct List_Nth_Element {
using value = typename List_Nth_Element<typename List::cons, N - 1>::value;
};
template<typename List>
struct List_Nth_Element<List, 0> {
using value = typename List::value;
};
template<template <typename, typename> typename Func, typename Init, typename List, bool = std::is_same<typename List::type, void>::value>
struct Fold :
public Lambda<Init, Func<typename List::type, Init>, Init, List>
{
using value = Init;
};
template<template <typename, typename> typename Func, typename Init, typename List>
struct Fold<Func, Init, List, false> :
public Lambda<Init, Func<typename List::type, Init>, Init, List>
{
using value = Func<typename List::value, typename Fold<Func, Init, typename List::cons>::value>::value;
};
template<template <typename> typename Func, typename List, bool = std::is_same<typename List::type, void>::value>
struct Map :
public Lambda<List, Func<typename List::type>, List>
{
using value = ::List<void, void>;
};
template<template <typename> typename Func, typename List>
struct Map<Func, List, false> :
public Lambda<List, Func<typename List::type>, List>
{
using value = ::List<typename Func<typename List::value>::value, typename Map<Func, typename List::cons>::value>;
};

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src/main.cpp Normal file
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#include "Data.hpp"
#include "List.hpp"
#include <iostream>
#include <type_traits>
constexpr uint32_t add(uint32_t left, uint32_t right) {
return left + right;
}
int main(int argc, char** argv) {
using list = ListConstructor<Number<3>, Number<7>, Number<4>, Number<12>>::value;
using result = Fold<NumericAdd, Number<0>, typename Map<NumericDouble, list>::value>::value;
}
// using first = List_Nth_Element<list, 0>::value;
// using second = List_Nth_Element<list, 1>::value;
// using third = List_Nth_Element<list, 2>::value;
// using fourth = List_Nth_Element<list, 3>::value;
// // using fifth = List_Nth_Element<list, 4>::value;
//
// using incremented = NumericIncrement<first>::value;
//
// using addition = NumericAdd<second, fourth>::value;
//
// using sum = Fold<NumericAdd, Number<0>, list>::value;
//
//
// return 0;
// }
//