谷歌发布开源开发语言 Carbon : 号称将替代 C++

项目的 Github 地址为： https://github.com/carbon-language/carbon-lang

在近日举行的 CppNorth 开发者大会上，谷歌工程师 Chandler Carruth 宣布了名为 “Carbon” 的全新开源开发语言，并称它将是 C++ 的继任者。Chandler Carruth 表示，Carbon 拥有与 C++ 的“双向互操作性”，也就是说开发者可以直接在 Carbon 语言的程序中使用 C++，这大大提升了项目迁移的便捷性。

谷歌在开发该语言的时候，就将接替 C++ 作为了核心目标，它拥有大量与 C++ 相契合的特性，一个熟练的 C++ 开发者将能够迅速上手 Carbon ，并熟练进行程序的编辑

C++

// C++:
#include <math.h>
#include <iostream>
#include <span>
#include <vector>

struct Circle {
  float r;
};

void PrintTotalArea(std::span<Circle> circles) {
  float area = 0;
  for (const Circle& c : circles) {
    area += M_PI * c.r * c.r;
  }
  std::cout << "Total area: " << area << "\n";
}

auto main(int argc, char** argv) -> int {
  std::vector<Circle> circles = {{1.0}, {2.0}};
  // Implicitly constructors `span` from `vector`.
  PrintTotalArea(circles);
  return 0;
}

Carbon

// Carbon:
package Geometry api;
import Math;

class Circle {
  var r: f32;
}

fn PrintTotalArea(circles: Slice(Circle)) {
  var area: f32 = 0;
  for (c: Circle in circles) {
    area += Math.Pi * c.r * c.r;
  }
  Print("Total area: {0}", area);
}

fn Main() -> i32 {
  // A dynamically sized array, like `std::vector`.
  var circles: Array(Circle) = ({.r = 1.0}, {.r = 2.0});
  // Implicitly constructs `Slice` from `Array`.
  PrintTotalArea(circles);
  return 0;
}

Mixed

// C++ code used in both Carbon and C++:
struct Circle {
  float r;
};

// Carbon exposing a function for C++:
package Geometry api;
import Cpp library "circle.h";
import Math;

fn PrintTotalArea(circles: Slice(Cpp.Circle)) {
  var area: f32 = 0;
  for (c: Cpp.Circle in circles) {
    area += Math.Pi * c.r * c.r;
  }
  Print("Total area: {0}", area);
}

// C++ calling Carbon:
#include <vector>
#include "circle.h"
#include "geometry.carbon.h"

auto main(int argc, char** argv) -> int {
  std::vector<Circle> circles = {{1.0}, {2.0}};
  // Carbon's `Slice` supports implicit construction from `std::vector`,
  // similar to `std::span`.
  Geometry::PrintTotalArea(circles);
  return 0;
}