In short, it aims to help evolve C++ itself, not to be a "C++ successor."
What it isn't. Cpp2 is not a successor or alternate language with its own divergent or incompatible ecosystem. For example, it does not have its own nonstandard incompatible modules/concepts/etc. that compete with the Standard C++ features; it does not replace your Standard C++ compiler or other tools; and it does not require any changes to your Standard C++ compiler or standard library or other libraries or tools to keep fully using all of them.
What it is. Cpp2 aims to be another "skin" for C++ itself, just a simpler and safer way to write ordinary C++ types/functions/objects, and a faster way to experiment with proposals for future new Standard C++ features in a simpler compiler and syntax flavor. It seamlessly uses Standard C++ modules and concepts requirements and other features, and it works with all existing C++20 or higher compilers and libraries and tools right out of the box with no changes required to use them all seamlessly and directly with zero overhead.
One-line HelloWorld (hello.cpp2):
main: () = std::cout << "Hello, world!\n";
More interesting version:
main: () = {
words: std::vector = ( "Alice", "Bob" );
hello( words[0] );
hello( words[1] );
}
hello: (msg: std::string_view) = {
std::cout << "Hello, (msg)$!\n";
}
This transpiles to:
#define CPP2_IMPORT_STD Yes
#include "cpp2util.h"
auto main() -> int;
auto hello(cpp2::in<std::string_view> msg) -> void;
auto main() -> int{
std::vector words {"Alice", "Bob"};
hello(CPP2_ASSERT_IN_BOUNDS_LITERAL(words, 0));
hello(CPP2_ASSERT_IN_BOUNDS_LITERAL(std::move(words), 1));
}
auto hello(cpp2::in<std::string_view> msg) -> void {
std::cout << ("Hello, " + cpp2::to_string(msg) + "!\n"); }
Last modified 28 April 2025