- Objective for 2023: get ready to evaluate the Carbon Language.
- Key results in 2023
- A concrete definition of our Minimum Viable Product for evaluation, the 0.1 language
- Complete design coverage of the 0.1 language's necessary features
- Complete 0.1 language implementation coverage in the Carbon Explorer
- A toolchain that can build a minimal mixed C++ and Carbon program
- Give talks at 2-3 conferences covering 3-4 different Carbon topics
- Beyond 2023
Our focus throughout 2023 will be to get the Carbon Language and project ready for serious evaluation of the experiment. There are two aspects to this evaluation:
- The language and tools need to be complete enough to evaluate.
- The users and communities we are targeting need both context and awareness of the technical ideas and design principles on which Carbon is built.
While we have talked about our 0.1 language, or our Minimum Viable Product (MVP) for evaluation purposes, we need to pin down exactly what this includes. We need concrete milestones that need to be reached for us to have confidence in potential users and communities being able to evaluate Carbon as a successor to C++.
We expect this to include a reasonably precise set of requirements across:
- Necessary language features
- Nice-to-have features
- Features can we omit and reasonably expect to not obstruct credible evaluation
- Implementation coverage of those features in the Carbon Explorer to validate the design
- Implementation coverage of those features in the toolchain
- Quality of implementation in the toolchain, both in general and for specific features
- Necessary documentation, strategy, or other supporting material
We expect this to also include at least enough of Carbon's features and C++ interop to support our basic example.
Note that we don't expect to finish implementing the 0.1 design in 2023. Our goal is to make sufficient progress that we can complete the implementation in 2024, but there are still many things that can go wrong and cause significant delays.
This year we plan to finish the design of the necessary feature-set that we define above for the 0.1 language.
We expect to complete the level of Carbon Explorer validation of the design needed for 0.1 in 2023 so that we have high confidence in the design's cohesion and behavior.
Our end goal is to compile a minimal but non-trivial example of bi-directionally mixing C++ and Carbon code such as our main example and run it successfully. However, completing everything involved in this example isn't expected to be realistic by the end of the year. We expect to work towards this example and in rough priority order across the following interop features and all the Carbon features they depend on:
- Calling C++ functions from Carbon.
- Importing concrete C++ types as Carbon types.
- Using Carbon generics with a C++ type in Carbon.
- (stretch) Calling Carbon functions from C++.
- (stretch) Importing concrete Carbon types into C++.
We want to engage both more broadly and in more depth with the C++ community as the Carbon 0.1 language becomes increasingly concrete. This should help set the stage for evaluations of Carbon when 0.1 is finished and available. To broaden our engagement, we want to give talks at 2-3 conferences spanning 2-3 geographic regions.
We also want these talks to provide the C++ community a deeper understanding of the Carbon language and project, spanning 3-4 different topics. For example, we might share the details of the language design, governance, and implementation.
Longer term goals are hard to pin down and always subject to change, but we want to give an idea of what kinds of things are expected at a high level further out in order to illustrate how the goals and priorities we have in 2023 feed into subsequent years.
As we adjust our schedule and roadmap to reflect the realistic rate of progress, the earliest it seems feasible to have everything we need to evaluate the 0.1 language is 2024. However, this is just a lower bound. We may discover as we progress things that further push out the schedule here. That is the nature of an experimental project like Carbon.
We expect that once we reach this milestone the community will be able to start realistically evaluating Carbon as a C++ successor language. Of course, this evaluation will take some time.
Once Carbon is moving quickly and getting public feedback, we should be able to conclude the experiment. We should know if this is the right direction for moving C++ forward for a large enough portion of the industry and community, and whether the value proposition of this direction outweighs the cost.
However, there will still be a lot of work left to make Carbon into a production quality language, even if the experiment concludes successfully.
Some concrete goals that might show up in this time frame:
- Self-hosting toolchain, including sufficient Carbon standard library support.
- Expand design of standard library to include, at least directionally, critical and complex areas. For example: concurrency/parallelism and networking/IO.
- Migration tooling sufficient to use with real-world libraries and systems. This might be used to help with self-hosting Carbon, as well as by initial early adopters evaluating Carbon.
- Create a foundation or similar organization to manage the Carbon project, separate from any corporate entities that fund work on Carbon.
A major milestone will be the first version of a production language. We also plan to finish transferring all governance of Carbon to an independent open source organization at that point. However, we won't know what a more realistic or clear schedule for these milestones will be until we get closer.
Goals in this time frame will expand to encompass the broader ecosystem of the language:
- End-to-end developer tooling and experience.
- Teaching and training material.
- Package management.
- Etc.