This was originally drafted as response to [Jo Rabin's blog post] discussing a meetup the W3C TAG hosted last month. For some reason, I was having difficulty adding comments there.
Hi Jo,
Thanks for the thoughtful commentary, and for the engaging chat at the meetup. Your post mirrors some of my own thinking about what the TAG can be good for.
I can't speak for everyone on the TAG, but like me, most of the new folks who have joined have backgrounds as web developers. For the last several months, we've been clearing away old business from the agenda, explicitly to make way for new areas of work which mirror some of your ideas. At the meeting which the meetup was attached to, the TAG decided at the urging of the new members to become a functional API review board. The goal of that project is to encourage good layering practice across the platform and to help WGs specify better, more coherent, more idiomatic APIs. That's a long-game thing to do, and you can see how far we've got to go in terms of making even the simplest idioms universal.
Repairing these sorts of issues is what the TAG, organizationally, is suited to do. Admittedly, it has not traditionally shown much urgency or facility with them. We're changing that, but it takes some time. Hopefully you'll see much more to cheer in the near future.
As for the overall constituency and product, I feel strongly that one of the things we've accomplished in our efforts to reform the TAG is that we're re-focusing the work to emphasize the ACTUAL web. Stuff that's addressable with URLs and has a meaningful integration point with HTML. Too much time has been wasted worrying about problems we don't have, or for good reasons, are unlikely to have. Again, I don't speak for the TAG, but I promise to continue to fight for the pressing problems of webdevs.
The TAG can use this year to set an agenda, show positive progress, and deliver real changes in specs. Already we're making progress with Promises, constructability, layering (how do the bits relate?), and extensibility. We also have a task to explain what's important and why. That's what has lead to efforts like the Extensible Web Manifesto. You'll note other TAG members as signatories.
Along those lines, the TAG has also agreed to begin work on documents that will help spec authors understand how to approach the design process with the constraints of idiomaticness and layering in mind. That will take time, but it's being informed by our direct, hands-on work with spec authors and WGs today.
So the lines are drawn: the TAG is refocusing, taking up the architectural issues that cause real people real harm in the web we actually have, and those who think we ought to be minding some other store aren't very much going to like it. I'm OK with that, and I hope to have your support in making it happen.
Regards
One strain of objection I often hear about the project of making the web more extensible is that it implies travelling further down the JavaScript rabbit hole. The arguments often include:
- No other successful platform is so limited to a single language (in semantics if not syntax).
- Better languages exist and, surely, could be hooked up to the HTML DOM instead.
- JavaScript can't really describe everything the web platform does, so it's not the right tool for this archeological excavation.
These, incidentally, are mirrors to the fears that many have about the web becoming "too reliant" on JavaScript. But that's a topic for another post.
Lets examine these in turn.
The question of what languages a platform admits as first-class isn't about the languages -- not really, anyway. It's about the conventions of the lowest observable level of abstraction. We have many languages today that cooperate at runtime on "classical" platforms (Windows/Linux/OSX) and the JVM because they collaborate on low-level machine operations. In the C-ish OSes, that's about moving words around memory area and using particular calling conventions for structuring input and outputs to kernel API thunks. Above that it's all convention; see COM. Similarly, JVM languages interop at the level of JVM bytecode.
The operational semantics of these platforms are incredibly low level. The flagship languages and most of the runtime behavior of programs are built up from these very low-level contracts. Where interop happens at an API level, it's usually about a large-ish standard library which obeys most of the same calling conventions (even if its implementation is radically different).
The web has it the other way around. It achieved broad compatibility by starting the bidding at extremely high level semantics which, initially, had very little in the way of a contract beyond bugwards compatibility with whatever Netscape or MSFT shipped last. The coarse, interpret-it-as-you-go contract of HTML is one of the things that has made it such a hardy survivor. JavaScript was added later, and while it has lower-level operational semantics than HTML or CSS, that history of bolting JS on later has led to the current project of encouraging extensibility and layering; e.g., through Web Components. It's also why those who cargo-cult their experiences of other platforms onto the web find themselves adrift. There just isn't a shared lower level on which to interoperate.
That there aren't other languages interfacing with the web successfully today is, in part, the natural outcome of a lack of shared lower-level idioms on which those languages could build-up runtimes on. It's no accident that CoffeeScript, TypeScript, and even Dart find themselves running mostly on top of JS VMs. There's no lower level in the platform to contemplate.
Which brings us to the second argument: there are other, better languages...surely we could just all agree on some bytecode format for the web that would allow everyone to get along...right?
This is possible, but implausible.
Implausibility is the only reason I pour time and effort into trying to improve JS and not something else. The Nash Equilibrium of the web gives rise to predicable plays: assuming that incentives for adopting low-level descriptions of JS (as any such bytecode would have to describe JS as well as everything else) are not evenly distributed, movement by any group that is not all of the competitors stymies compatibility, which after all is the whole goal. Any language that wishes to interoperate with JavaScript and the existing DOM is best off describing its runtime in terms of JavaScript for fear that the threat to not adopting a compatible bytecode is credible. Compatibility strategies that straddle the fence can work, but it's not a short (or clear) game to play. And introducing an abstraction that's not fundamentally lower-level than JS (and/or does not fully subsume its semantics) is simply doomed. It would lack the power to even credibly hold out hope for a compatible future.
So, yes, there are better languages. Yes, you could put them in a browser. But unless you possess the power to put them in every browser, they don't matter unless their operational semantics are 1:1 with JavaScript.
You can see how I ended up on TC39. It's not that I think JS is great (it has well-documented flashes of genius, but so does any competitor worth mentioning) or even the perfect language for the web. But it is the *one language that every vendor is committed to shipping compatibly*. Evolving JS has the leverage to add/change the semantics of the platform in a way that no other strategy credibly can, IMO.
This leaves us with the last objection: JS doesn't fully describe everything in the web platform, so why not recant and switch horses before it's too late to turn back?
This misreads platforms vs. runtimes. All successful platform have privileged APIs and behaviors. Successful, generative platforms merely reduce the surface area of this magic and ensure that privileged APIs "blend in" well -- no funky calling conventions, no alien semantics, etc. Truly great platforms leave developers thinking they're the only ship in the entire ocean and that it is a uniform depth the whole way across. It's hard to think of a description any more at odds with the web platform. Having acknowledged the necessity and ubiquity of privileged APIs, the framing is now right to ask: what can be done about it?
I've made it my work for the past 3+ years -- along with a growing troupe of fellow thinkers -- to answer this charge by reducing the scope and necessity of magic in everyday web development. To describe how something high-level in the platform works in terms of JS isn't to deny some other language a fair shot or to stretch too far with JS, it's simply to fill in the obvious gaps by asking the question "how are these bits connected?"
Those connections and that archeological dig are what are most likely to turn up the sort of extensible, layered, compatible web platform that shares core semantics across languages. You can imagine other ways of doing it, but I don't think you can get there from here. And the possible is all that matters.
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