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by andralex 3945 days ago
This is he. AMA!
9 comments

My background was high assurance systems and security plus regular software/system development. Mainly do R&D now while evangelizing field's developments. The academic and industrial side of the field keep making great progress in transformation (see Semantic Designs), static checking (Astree Analyzer), compilation (CompCert), better optimization, and so on. The main thing that hurts such work, though, is when the language and/or its standard get too complex or vague. C++ was horrid in this regard.

So, as you try to formalize it, I encourage you to try to remove as much ambiguity and processing complexity as possible. Maybe also work with academics who specialize in formal specs or methods that caught many defects in prior language or system specs. The result is that researchers interested in building assurance and QA tools for D will have a much easier time. Just look at how long it took to certify a C compiler vs ML and LISP compilers despite latter languages being much more powerful.

Reason it's important, whether an immediate concern or not, is that much of the best stuff comes from cash- and time-strapped, but smart, academics trying to make a name or push state-of-the-art. Easier your language is to work with, the more of them might choose it. And you've done a really, good job on a C++ replacement that I thought would've had more adoption. So, I'd like to see some of those brains get put on your work, too. :)

Regardless, good luck to you on your next move!

Looks like the target audience for C++ mindshare is being taken away by Golang and Rust. When I think of "D" I think of nothing but "oh, yeah, they use it at Facebook". Who else uses it? How do you see Golang and Rust as competition?
D would be definitely helped by a large corporate sponsor. I think the foundation will make the language a more serious alternative for such adoption.

Competition is good for all involved. Rust and C++ are the competitors closer to the same turf. I think we have a solid value proposition and several ways to enhance it and differentiate ourselves. Time will tell.

We built all of our machine learning backend in D at AdRoll. Some examples:

- learning of large-scale classifiers and regressors using custom optimizers

- real-time pricing of billions of ads a day using these models on ad exchanges. <.5ms latency to parse complex bid requests and compute sparse and simd dense dot-products

- a real-time event processing system that hits DynamoDB with ~4.5K json queries per sec on a single node

We literally have D systems deployed on hundreds of ec2 instances as we speak and responsible for mission critical tasks of a >100$M run rate company. D is ready for prime time and works at scale.

And we embed D in our large-scale Erlang deployments, too.

It's a fun time.

>> D is ready for prime time

Not on ARM. I will try again but last time I tried setting up a toolchain (~6 months ago) met with headache, pain, and eventually heartache.

Thanks for sharing!
Is there a lot of C++ to go traffic ? I have not seen much along those lines. Go doesn't remotely look like a language that a C++ programmer would be interested in. Given its limitation go is an ok enough language but that's about it.
> Who else uses it?

http://wiki.dlang.org/Current_D_Use

And many more companies not in that list.

Never heard of any of them besides Facebook. Anyone famous?
Remedy and Funatics developed popular games. Though it's not said what they used "D" for.

Remedy is responsible for Alan Wake and Max Payne, Funatics for Cultures, Zanzarah, among others.

By following the links in the wiki:

Remedy: "integrating D with a typical C/C++ game engine as an extension language for use processing game logic"

Funatics: "D as a replacement for the parts of our infrastructure that use nodejs right now"

Pretty big names in their field.
Pardon my ignorance, but do you have some kind of roadmap for D ? What features do you prioritize to develop or enhance ? Will D focus on concurrency (Erlang's domain) first, RAD web app/service (PHP, Java, and Ruby's domain), or something else ?
I have quite a few things in mind for the immediate future. Organizationally, I want to get the D Language Foundation rolling as an organizational mothership of the language. Technically, I want to focus on: (a) completely defining the language - fuzzy corners such as the meaning of "shared" are a liability; (b) offer a solid experience to users who don't want a garbage collector; and (c) design more libraries using the fledgling Design by Introspection technique.

(EDIT sorry, submitted too soon) With regard to targeted users and uses, D is an ample language that could be used for a large range (heh) of applications. I want to make sure the core language and libraries offers a solid support on which various applications, frameworks, and libraries can build.

>> D is an ample language that could be used for a large range (heh) of applications. I want to make sure the core language and libraries offers a solid support on which various applications, frameworks, and libraries can build.

The advice given in marketing new products is often opposite - find a niche, offer much better value than competitors for that niche ,become the leader of that niche - and use that base to expand.

I wonder if this kind of advice offers a better route for success for a programming language ? What was the case historically ?

This is good food for thought. Yes, working through a niche has been a good "in" for some languages.
I feel this advice leaves a lot to be desired.

Ruby was around for 10 years before Rails released version 1.0. Rails itself didn't get popular until version 2, 4 years later.

It takes a long time for a language to mature to the point to where someone loves it so much they're willing to bet their career on it, as DHH did.

The best thing for a language designer to do IMO is not to try to decide what the killer app is, but rather to make it as nice as possible so that more and more people want to use it to solve problems.

Rails isn't the best web development stack because of any kind of monolithic effort on the part of the Ruby core team. It was built on top of the work of dozens of programmers who did things like write HTTP client libraries, HTML parsing tools, templating languages, all the things that a framework relies completely on.

My advice: You can only focus on so much at once. Let the community build the tools. You build the language. You'll never be able to do both, there just isn't enough time.

There's so much other stuff for you to do. Figure out governance, setting a tone for the community, reaching out to heavyweights so as to raise your profile, working out what your relationship to corporate sponsors is, how you're going to ensure stability across versions, package management. The countless little things that make one language more of a joy to work with than another.

I'm pretty sure there's a market for D on consoles and mobile gaming. This is the first thing I get asked every time I suggest using D at work (we mainly do casual games while also porting AAA titles with a few internal engines).

So far I've only been successful with a few shell scripts calling into the tools of the console's SDK doing mass reflection on 75k shader object files among other things. Yet I do half of my home projects in D and absolutely love it.

I think getting D to interopt with more existing code in all of C#, Java and Objective-C as well as on both mobile devices and game consoles will greatly help its adoption with the "oh its just another library we add to our existing codebase" factor which has tremendously helped Clojure take off.

This means D could make it easy to extend both JVM and CLR applications with lighting fast code while getting free access to their respective ecosystems. I for one would love to use D instead of C# to write Unity code.

Clojure isn't really a fair comparison. Clojure hasn't got low-level interop with all those things, just JVM, and that interop is bought at the cost of closely tying Clojure to JVM. I don't think D can be changed in all the basic ways that would be required to give it the same level of integration with JVM, and that would also basically mean abandoning the entire standard library. JVM's difficulties integrating with things other than JVM aren't something I imagine D can really solve.
1. I read you were rewriting the GC, is that still on track?

2. is there any plan to include Mobile(mainly iOS/Android) in the D roadmap?

3. any plans to safely use the standard library with GC disabled?

1. I got std.experimental.allocator accepted for inclusion. On its basis it's not difficult to build the structures and algorithms necessary for garbage collection.

However, there were two concurrent developments. One is Martin Nowak and others did great work on improving D's existing garbage collector. The other trend is that it became increasingly clear that a category of users will always be weary of a GC, be it for the right or wrong reasons. So the better place to hit is to offer a great experience in D without requiring any garbage collection at all.

2. Mobile is an important area for a language like D. We don't have many experts on team to work on that, but we're looking. One thing I can do soon is to encourage ARM support, which right now works only experimentally and in a science project kind of way.

3. I want to make it possible to use a well-defined subset of the standard library without a GC. (The subset part is for legacy compatibility.)

Mult succes in continuare ! :)
Multzam!
My question: Why? I mean, why this decision for your personal career?
I want to work on something where I can make a difference, and I think this is it. Paul Graham wrote (paraphrased from http://www.paulgraham.com/procrastination.html) one should at best work on things likely to be part of one's obituary. At this point I feel there'd be little difference if my obituary read "worked for 6 years at Facebook" vs. 7, 8 etc. But if I helped people get code written better, that's a lure I wasn't willing to not seize.
I followed D for sometime, it has taken all the good parts from other languages in an incremental manner - contracts / actors/ functional concepts.

Do you vision D becoming a transpiler platform, similar to JavaScript land where languages target D source ?

x-lang => D => ldc => binary

Probably not; D is not a particularly suited language for being a backend target. To be fair, neither is Javascript; it got in that position by accident.

That said, just as a related aside, there's the Daniel Murphy's magicport program that translates real projects from C++ do D semiautomatically (Daniel used it to translate the D compiler itself; we recently committed to bootstrapping).

Could you please elaborate on why D is not a good backend language? Knowing the little I know about it, I assumed that would be a good start for it.
I fixed a bug in Flint; do you have an equivalent of the Knuth $2.56 check?

On a serious note... what do you think you will miss the most about Facebook?

The income :o). Well, just kidding. I think the best thing about Facebook is its people. They are really really good, and that's felt at all levels.
Whats the status of std.stream?
I think the lack of demand for it has been an indicator that ranges with additions are just enough. We're currently looking at adding optional primitives to ranges in a Design by Introspection manner to support bulk streaming of data.
I would definitely love to see range primitives support bulk streaming!

How about adding a byte buffer concept alongside with ranges? I'm thinking an API similar to Netty's ByteBuf but using D's compile-time capabilities instead. These would be valid ranges as well but offer direct byte access on top.

Also, while on the subject of status updates, what's the status of std.reflection? Any chance UDAs could be included in there? :)

It would be great if the reflection info could be outputted to a separate file for those cases where its only needed during program initialization or used by external tools.

Not AA, but streams have been pretty much deprecated in favor of ranges.
Aren't ranges and streams conceptually different? Ranges are for data traversals and streams are for data transfers.

I want more than empty, front and popFront to manipulate byte buffers with high performance.

I'm thinking about reading data structures, performing bit conversion, and extracting primitive values from untyped byte arrays. Going as far as to reuse the array's memory for the values being read which isn't possible with ranges.