EXOTIC.lyst

EXOTIC.lyst is a high-performance, header-only C++ library for managing and manipulating typelists. Part of the EXOTIC collection of modern C++ libraries, it provides a full suite of compile-time type operations optimized for template metaprogramming (TMP).

---

Table of Contents

• Features

• Installation

• Usage

  • Typelist Basics
  • Operations

• Type Utilities

• License

• Author

---

Features

• Fully header-only C++ library, no dependencies outside the standard library.

• Compile-time typelist operations:

  • Access elements: at, front, back
  • Modification: push_front, push_back, replace, pop_front, pop_back
  • Filtering and transformation of types
  • Concatenation of typelists
  • Counting and searching types: count, index_of, contains

• Advanced TMP helpers and type traits in EXOTIC::Utility

• Zero runtime overhead: all operations are resolved at compile time

• Compatible with modern C++ standards (C++17 and later recommended)

---

Installation

Simply include the header in your project:

#include "EXOTIC.lyst.h"

No compilation or linking steps are required, as this is a header-only library.

---

Usage

Typelist Basics

A typelist is a compile-time list of types:

using MyTypes = EXOTIC::Lyst::typelist<int, float, double>;

Check if a typelist is empty:

static_assert(!EXOTIC::Lyst::empty_v<MyTypes>, "Typelist should not be empty");

Access elements:

using FirstType  = EXOTIC::Lyst::front_t<MyTypes>;  // int
using LastType   = EXOTIC::Lyst::back_t<MyTypes>;   // double
using SecondType = EXOTIC::Lyst::at_t<1, MyTypes>;  // float

---

Operations

Modify typelists at compile time:

// Push and pop types
using Extended = EXOTIC::Lyst::push_back_t<char, MyTypes>; // int, float, double, char
using Shorter  = EXOTIC::Lyst::pop_front_t<Extended>;      // float, double, char

// Replace a type
using Replaced = EXOTIC::Lyst::replace_t<1, long, MyTypes>; // int, long, double

// Filter types based on a predicate
template<typename T>
struct is_integral_type : EXOTIC::Utility::is_same<T, int>::type {};

using Filtered = EXOTIC::Lyst::filter_t<is_integral_type, MyTypes>; // int

// Transform types
template<typename T>
struct add_pointer { using type = T*; };

using PointerTypes = EXOTIC::Lyst::transform_t<add_pointer, MyTypes>; // int*, float*, double*

Other available operations:

• concat_t<L1, L2> – concatenate two typelists
• remove_first_t<T, L> – remove the first occurrence of a type
• remove_all_t<T, L> – remove all occurrences of a type
• reverse_t<L> – reverse the order of a typelist
• count_v<T, L> – count how many times a type appears
• contains_v<T, L> – check if a type exists in a typelist
• index_of_v<T, L> – get the compile-time index of a type

---

Type Utilities

EXOTIC::Utility provides TMP and type trait helpers:

• size_v<L> – get typelist size
• is_same_v<T, U> – check if two types are the same
• is_void_v<T> / is_not_void_v<T> – check for void types
• dependent_false_v<T> – helper for static_assert in templates

These utilities enable safer, more readable TMP code.

---

License

This library is licensed under the Boost Software License, Version 1.0. See LICENSE for details.

---

Author

Félix-Olivier Dumas GitHub: unrays/Lyst Version: 1.0.0 Last Updated: January 15, 2026

I had zero experience with typelists before this. I built Lyst in 5 intense days and am proud of the work.