One template argument to rule them all!

Are you tired of not being able to set template arguments to string literals?
Are you tired of every possible workaround leading to tons of boilerplate and increased build times?
Well... today's your lucky day!

Check this out:

#include <Langulus/Literal.hpp>

using namespace Langulus;

template<literal_t T = 0>
consteval auto foo() { return T; }

constexpr auto demo1 = foo<>();
constexpr auto demo2 = foo<5>();
constexpr auto demo3 = foo<5.5f>();
constexpr auto demo4 = foo<true>();

// ...*drum roll*...

constexpr auto demo5 = foo<"hello there">();

---

✅ C++23
✅ Fully supporting constexpr/consteval
✅ Will throw on range errors when LANGULUS_OPTION_SAFE_MODE is defined
✅ Tested on Clang 19, GCC 14.2, MSVC v143, Clang-CL 19

Caution

Not supported on MSVC yet (as of 11.2025). They have a lot of catching up to do with C++23 in order for this to work properly on their compiler.

---

literal_t acts as both a single value, or string literal. You can use it as a template parameter. Similar implementation should be introduced in C++26 as std::fixed_string, supposedly...

String literals of different sizes result in unique types, and thus can't often be used with ternary operators, so I've taken the liberty to allow for strings of the form ? "\0\0\0" : "alt" - left literal_t has ArraySize == 4, but size() == 0.
So you can do fun stuff at compile time, like:

constexpr literal_t Name = same_as<int32_t, int> ? "i\0\0" : "i32";

This also allows us to do some neat compile speed/memory optimizations by minimizing template instantiation via CTAD. literal_t's template will always instantiate with ArraySize being a power-of-two, regardless of the string's null-terminated length.

---

Getting it:

include(FetchContent)
FetchContent_Declare(LangulusLiteral
    GIT_REPOSITORY  https://github.com/Epixu/literal_t.git
    GIT_TAG         main
    EXCLUDE_FROM_ALL
)
FetchContent_MakeAvailable(LangulusLiteral)

target_link_libraries(YourTarget PUBLIC LangulusLiteral)

Alternatively, you can always just copy the include/Langulus/Literal.hpp header, if you prefer to keep it simple.