Ask HN: What Happened to Lambda-the-Ultimate.org?

The only other place I know that discusses PL stuff is https://www.reddit.com/r/ProgrammingLanguages/. The discussion there's not always high quality, but sometimes there are interesting topics.

Does anyone know of any other good places where PL theory and topics are are discussed?

[1]: http://webcache.googleusercontent.com/search?q=cache:XjPUGeG...

The language wars largely ended, with the more popular languages folding in a lot of the more (at the time) esoteric features.

DSLs have fallen out of favor.

Javascript took over for a bit (although I believe that is receding.)

LtU was a great place for about a decade when the internet was getting going, moving language discussions out of the mailing lists, which were pretty isolated, and into a general forum. It was a great place for a while, and I anticipate it might be a great one again if DSLs resurge in popularity.

Speaking of which, here is mine :)

https://hyperscript.org

LTU was hardly about DSLs or even particular languages, though of course that came up on and off. It was fundamentally a place with discussions on PL theory and related stuff, with the front page being predominantly about current papers. So, the success of Javascript/drop in DSL popularity seem like a strange reason for LTU to stop being useful.

Perhaps my biases though: maybe there was some other reason why LtU ended up getting a lot quieter.

> DSLs have fallen out of favor.

External DSLs have largely fallen out of favor, in a large part because the “esoteric features” that have been widely adopted include those that enable very expressive internal DSLs.

If we had grammars that were really extensible (add "unless(X)" equivalent to "if(!X)" in Java's grammar with a few lines of code) and composable (stick a SQL statement into a Java program with just a few lines of code if you have the SQL and Java grammars) and reversible (turn the AST tree back to source code) it would be a lot more fun writing external DSLs.

Every so often a revolution gets promised, like PEG parsers for Python, but then people get worried about how fast the parser is again and it isn't like Heinlein's Moon is a Harsh Mistress but more like Haldeman's Worlds (as Pete Townsend puts it "We won't get fooled again".)

If parsers were easier to use people might use them 10x as often as they do today.

Agreed. I've tried various different approaches to building external DSLs, from fully hand-written to language workbenches like xtext [0] and spoofax [1]. I always end up back at hand written, often because of error handling. Creating meaningfully helpful error handling with parser generators always seems hard.

>If we had grammars that were really extensible

Grammar composition is hard. Canonical BNF is top down, meaning alternate clauses are complete and closed in most parser generators. One notable exception is SF3[2] (part of Spoofax). It doesn't require alternate clauses to be grouped and so can support composable languages. It's the most flexible parser-generator I've used, and the syntax is pretty nice too.

Fun fact: SDF3 and Spoofax come from Eelco Visser's group at TU-Delft - the same group that originated Scope Graphs, the basis for Github's Stack Graphs [3].

[0] http://www.eclipse.org/Xtext/ [1] https://www.spoofax.dev/ [2] https://eelcovisser.org/publications/2020/AmorimV20.pdf [3] https://news.ycombinator.com/item?id=29500602

I think Java is just fine for internal DSLs, see

https://www.jooq.org/

I was also hacking on this project

https://github.com/paulhoule/ferocity/

which was about making Java homoiconic. Namely in ferocity you can write

   Expression<String> literal = of("Hello World");
   Expression<byte[]> expression = getBytes(literal);

   expression.asSource() = '"Hello World".getBytes()'
   expression.evaluate() = {72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100}

I got far enough on that project that I discovered a bunch of things like the expression language has extensions over the real Java language pretty naturally for instance if you have a quote function like the quote in LISP you can write programs in the extended language to process syntactic macros.

I convinced myself that the idea is sound and got started on bootstrapping it by building a partial implementation (ferocity0) and code generator to make stubs out of the standard library plus a persistent collections library because that is pretty helpful for building the DSL, then write ferocity1 in ferocity0 wherever it could eliminate boilerplate (like the 8 primitive types.)

Sad to see it go but it might just have self died.

(kidding)

Even if it's propped back up, having been extremely quiet for a prolonged period, and then conspicuously broken could pretty reasonably be expected to push participants to a different venue, don't you think?

I'd be happy to see the kind of discussions that happened on Lambda The Ultimate thrive anywhere, so long as it's reasonably open. Stack Exchange is pretty good because it puts content under a CC license: https://stackoverflow.com/help/licensing I thought there was a programming lanugage Stack Exchange but I'm just seeing https://softwareengineering.meta.stackexchange.com/ - and there's this question: https://meta.stackexchange.com/questions/309740/where-to-ask... On the other hand, StackExchange tends to resist open-ended questions. Perhaps a Discourse (cofounded by a Stack Overflow cofounder) would be a good spot.

I'm really hoping it will come back up even if it doesn't get new activity because archive.org isn't the same as being able to just link to an old post.