Carbon (programming language)

Carbon (programming language)
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Name	Carbon
Paradigm	Procedural programming, Object-oriented programming, Generic programming
Designer	Google, Chandler Carruth
Developer	Google
Latest release version	0.8
Latest release date	19 December 2024
Typing	Static typing, Type safety
Influenced by	C++, Rust (programming language), Kotlin (programming language)
Operating system	Linux, macOS, Microsoft Windows
License	Apache License

Carbon (programming language). Carbon is an experimental, general-purpose programming language created by Google as a potential successor to C++. It is designed to provide performance and low-level control comparable to C++ while offering modern language features, improved safety, and better developer ergonomics. The language aims to achieve seamless, bidirectional Interoperability with existing C++ codebases, allowing for incremental adoption within large-scale software projects.

Overview

Announced publicly in 2022 at the CPP North conference by Google engineer Chandler Carruth, Carbon is positioned as a "successor language" to the long-established C++. The project emerged from within Google's extensive C++ ecosystem, driven by challenges in evolving the older language's complex Technical debt. Unlike entirely new systems languages such as Rust (programming language), Carbon's primary goal is to serve as a compatible, incremental migration path for the vast global C++ community. Development is conducted openly on platforms like GitHub, with the language being released under the permissive Apache License.

Design and features

The design philosophy of Carbon emphasizes explicit goals over C++'s historical focus on backward compatibility. Key design pillars include performance matching C++, a foundation of modern Generic programming principles, and a commitment to Code readability. Language features are built to be foundational and orthogonal, avoiding the complex interactions seen in C++ Template metaprogramming. Important features include built-in support for Memory safety through mechanisms like Checked pointers, a robust Error handling model distinct from C++ Exception handling, and a simplified, consistent Type system. The language also introduces a new Build system and Package manager designed for its toolchain.

Syntax and semantics

Carbon employs a syntax that is deliberately more readable and less ambiguous than C++, drawing inspiration from languages like Kotlin (programming language) and Swift (programming language). It uses keywords such as `fn` to declare functions and `var` for mutable variable declarations, moving away from the C (programming language)-style syntax heritage. Semantically, it enforces stricter rules to prevent Undefined behavior common in C++; for example, Integer overflow is defined behavior. The language adopts Expression-based semantics where possible, and its Type inference system is more powerful and predictable, reducing boilerplate code compared to C++ Auto (C++).

Interoperability with C++

A cornerstone of Carbon's strategy is its deep, bidirectional Interoperability with C++, which is unprecedented for a new systems language. This is achieved not through a Foreign function interface but via direct Linking (computing) at the Binary-code compatibility level. Carbon code can call C++ functions, use C++ Class (computer programming) instances, and inherit from C++ Base classes seamlessly, and vice-versa. This design allows teams at organizations like Google or Microsoft to migrate modules incrementally without rewriting entire Codebases, a critical requirement for adoption in industries like High-frequency trading and Game engine development.

Development and tooling

The Carbon project is developed in the open, with its evolution guided by public Design documents and community feedback on GitHub. The toolchain is a major focus, featuring a LLVM-based Compiler named `carbon-explorer`. Alongside the compiler, the project is developing a dedicated Package manager and Build system to address the fragmented state of C++ tooling, often involving CMake or Bazel (software). The development process emphasizes comprehensive Documentation and a suite of Software testing tools to ensure stability as the language evolves from its current experimental status toward a potential version 1.0.

Comparison with other languages

Carbon is most directly compared to Rust (programming language) and C++. Unlike Rust (programming language), which introduces a novel Ownership (computer science) model and Borrow checker to guarantee Memory safety, Carbon aims for a gentler learning curve for C++ developers and prioritizes Interoperability. Compared to C++, Carbon offers a cleaner slate with modern defaults and safer abstractions, but does not yet have the maturity or Standardization of ISO/IEC JTC 1/SC 22. Other modern systems languages like Zig (programming language) or Julia (programming language) have different primary goals, such as simplicity or scientific computing, whereas Carbon's niche is explicitly as a C++ successor.

Category:Programming languages Category:Google software Category:Procedural programming languages Category:Object-oriented programming languages