swift uses c++20/23 concepts - Posted on Jun 18, 2024 - See https://www.swift.org/documentation/cxx-interop - Logs Home - d0024

Download and install swift latest snapshot

Download and install swift latest snapshot (6.0).

install libcxx

Install clang libc++

apt install libc++-dev libc++abi-dev

Create swift cpp project

Create swift c++ project.

Commands :

mkdir -p hello_swift/{Sources/hello_cpp/include,Sources/hello_swift}
cd hello_swift/
kak Package.swift

Package.swift :

// swift-tools-version: 6.0

import PackageDescription

let package = Package(
	name: "hello_swift",
	targets: [
		.target(
			name: "hello_cpp"
		),
		.executableTarget(
			name: "hello_swift",
			dependencies: ["hello_cpp"],
			swiftSettings: [.interoperabilityMode(.Cxx)]
		)
	]
)

cpp code

Commands :

cd Sources/hello_cpp/include/
kak any_name.cpp

c++ code :

any_name.cpp

#pragma once

#include <iostream>
#include <concepts>

namespace any
{

template <typename type_xtk>
concept number = std::integral<type_xtk> || std::floating_point<type_xtk>;

template <any::number type_xti>
class test
{
public:
	void print() const
	{
		constexpr auto value__ = static_cast<type_xti>(234.432);
		std::cout << "value__ : " << value__ << std::endl;
	}
};

class hello_cpp_any_name
{
public:
	void print() const
	{
		any::test<int>{}.print();
		any::test<float>{}.print();
	}
};

}	// namespace any

swift code

Commands :

cd -	# cd <project root dir>
cd Sources/hello_swift/
kak any_name.swift

swift code :

any_name.swift

import hello_cpp

class hello_swift
{
	public func print()
	{
		let object = any.hello_cpp_any_name()
		object.print()
	}
}

var hello = hello_swift()
hello.print()

var ob1 = any.hello_cpp_any_name()
ob1.print()

let ob2 = any.hello_cpp_any_name()
ob2.print()

build and run swift project

c++ compiler and linker flags must be passed to both "swift build" and "swift run" .

gcc libstdc++ latest c++20/23 can not work for swift compiler in the moment.

libc++ c++20/23 can work with swift compiler in the moment.

swift run -Xcc -std=c++23 -Xcc -stdlib=libc++ -Xlinker -lc++

$ swift run -Xcc -std=c++23 -Xcc -stdlib=libc++ -Xlinker -lc++
Building for debugging...
[1/1] Write swift-version-32A5E7755150B194.txt
Build of product 'hello_swift' complete! (0.01s)
value__ : 234
value__ : 234.432
value__ : 234
value__ : 234.432
value__ : 234
value__ : 234.432