Languages that encourage making DSLs are a two-edged sword. On the one hand, you get to make a language that is more clear and fine-tuned to your use-case. On the other, you have an ad-hoc language with no support that you have to maintain along with the documentation (considering that you can't expect anyone else to know the DSL ahead of time). As I've gotten older, I've determined that well-designed APIs in a well-known language are a better alternative to DSLs.
This is a successor to REBOL[0], designed by Carl Sassenrath[1] who designed the Amiga kernel.
I've looked it a few times over the years. It's neat. I've never written a single line of it, though.
I wrote a small app in REBOL once, just too automate some stuff for some managers in a job about 20 years ago. It's quite nice, but I don't think I'd want to write anything significant with it.
I don't remember how I found it, but REBOL was one of the first programming languages I learned around 25 years ago. Most of my personal projects are still written in it.
I have yet to try converting anything to Red.
"In 1988, Sassenrath left Silicon Valley for the mountains of Ukiah valley, 2 hours north of San Francisco. From there he founded multimedia technology companies such as Pantaray, American Multimedia, and VideoStream. He also implemented the Logo programming language for the Amiga, managed the software OS development for CDTV, one of the first CD-ROM TV set-top boxes, and wrote the OS for Viscorp Ed, one of the first Internet TV set-top boxes."
What a legend!
Right? And I think that's what keeps bringing me back to REBOL, and thus Red. They don't appeal to me on the face of them. Like, the code examples look interesting but in a "magical" kind of way that strikes a little bit of fear into my engineering heart. But with that kind of pedigree, I can't dismiss the ideas. If Sassenrath came up with it, I bet there's a kernel of awesomeness inside.
I suspect a lot of the magic will fall away after realizing the block data structure (the square brackets) are pretty close to a Lisp list. And just like in Lisp, they're used for both code and data. One big difference is words are evaluated by default instead of just the first word in a list, so there's nowhere near as much nesting, and whenever an expression ends the next one can begin with no delimiter (but use newlines for legibility).
pretty sure he finished out his post Rebol career with Roku
I used it once to build a simple web scraper and image downloader, and it worked really great for that. It was right in the wheelhouse for the language. (That was REBOL, not RED, and many years ago.) Honestly I'd just do it in Python, now, even though it's not as interesting.
This is what I used it for back in the day too. I was watching a demo of Robot framework for Selenium the other day and it reminded me of parsing pages with rebol. Not that they are similar, but perhaps because I thought rebol would be interesting to use with Selenium.
I figured they were cooked when they started doing weird cryptocurrency-related stuff. I really hope they get to their 1.0 release someday.
Same. I was regularly following it until they started talking about an ICO and began focusing too much on making a dialect for block chain stuff.
The idea between having the red system language, regular scripting language, cross platform gui, and native executables was really cool though. I remember being interested back in ~2015, so my question is...what's going on as it's been a decade. I know the project is crazy ambitious of course, but how close are we to where this is at a stage where most would consider it production worthy.
IIRC think their original roadmap had 1.0 around 2020. And that was going to include everything, including async written from scratch in a language where nothing was made for async.
Then the roadmap slipped, and then never mentioned again.
But I haven't looked at the language or discussions around it for a long while now.
Edit: found some old discussion here. In 2018 they were at version 0.6.4 https://news.ycombinator.com/item?id=18864840
In 2025 they are at version 0.6.6: https://github.com/red/red/releases
For me, it even went off the rails before, when Nenad went to China because he was able to raise funds for the project. But he hadn't anticipated that he would be in charge and not the other way around. The situation seems to suit him perfectly. I don't think Red has any future at this point. In any case, the roadmap has always been stratospheric.
can you elaborate what you mean by not anticipating that he would be in charge?
btw, i met him in beijing while he was there.
Interesting, that at least explains why this happens a little bit.
Holy nanny state. The authors of a language have thought about using cryptocurrency, so it's flagged as a phishing and scam site? Literally 1984.
It's a community maintained block list. You may be able to do something about it. So, not 1984 all the way.
Here [0] is an example of what it looks like. Took some digging to find, really should be more prominent on the site.
It's very elegant! I can't fully grasp everything that's happening but the visual appearance of the syntax alone is interesting.
[0] https://github.com/red/code/blob/master/Scripts/clock.red
I agree that this particular coding example looks good. I find it aesthetically pleasing for some reason. But like you I don’t know the language, which leaves me with a question, does this code make understanding the function’s operation and implicit usage contract (i.e. the function’s type) clear to a dev that does know the language?
I would assume it does, because I assume I be able to know these things in a comparable JS or Python example. But if that assumption is correct I really like the ‘look’ of Red.
Seems someone built an ETL product from XML to databases.
If it's robust it seems rather neat.
This is like the only programming language I could never learn. I just don't understand anything and I can't build any mental model of what's going on behind the hood
I wrote a paper on REBOL back in college. It is very interesting, but the syntax is definitely weird. You might think of the function call syntax as being sort of Forth-like, but with the tokens in reverse order. So like a Lisp, but without required parentheses. e.g. in the example
send friend@rebol.com read http://www.cnn.com
(send friend@rebol.com (read http://www.cnn.com))
Weirdly, the language also has some infix operators, which seem a bit out-of-place to me. I have no idea how the 'parser'[1] works.
[1] 'parsing' happens so late that it feels funny to call it that. The thing that knows how to treat an array as a representation of an evaluatable expression and evaluate it.
> Weirdly, the language also has some infix operators, which seem a bit out-of-place to me. I have no idea how the 'parser'[1] works.
There are no keywords or statements, only expressions. Square backets ("blocks") are used for both code and data, similar to a Lisp list. The main language (called the "'do' dialect") is entirely polish notation with a single exception for infix operators: Whenever a token is consumed, check the following token for an infix operator. If it is one, also immediately consume the immediately following one to evaluate the infix operator.
This results in a few oddities / small pitfalls, but it's very consistent:
* "2 + 2 * 2" = 8 because there is no order of operations, infix operators are simply evaluated as they're seen
* "length? name < 10" errors (if "name" isn't a number) because the infix operator "<" is evaluated first to create the argument to "length?"
From your brief description that is likely incomplete, it looks as if the length? function is treated as a prefix operator of low precedence relative to the infix operators. The infix operators are all at the same precedence level and have left-to-right associativity.
I made an infix parser in which certain prefix operators (named math functions) have a low precedence. This allows for things like
1> log10 5 + 5 ;; i.e. log10 10
1.0
2> - 5 + 5
0
3> log10 5 + 5 + log10 5 + 5 ;; i.e. (log10 5 + 5) + (log10 5 + 5)
2.0
4> len "123" - 2
** -: invalid operands "123" 2
The following are also the result of the "phony infix" hack:
4> 1 cons 2
(1 . 2)
5> 1 cons 2 + 3
(1 . 5)
Not sure why you got downvoted, but Rebol is not a Lisp. It doesn't work because of precedence rules or special rules, but because arguments accumulate until there are enough to eval the previous function in the stack, so you can do stuff like
print tostring 5 + cos pi
I know you enjoy Lisps, so you might like this toy Rebol evaluator written in Scheme: http://ll1.ai.mit.edu/marshall.html
but why, don't get this design choice at all.
It takes the common "function(arg1, arg2)" pattern and turns (almost) the whole language into a very simple/consistent https://en.wikipedia.org/wiki/Polish_notation
Even things that are normally keywords and statements in other languages (like conditionals and loops) are actually just functions that conform to the exact same parsing rules.
it's lisp with square braces instead of parens (and then a whole bunch of other random things like a gui library in the standard library?)
It's actually more like Logo, which is Lisp with square brackets instead of parens and fixed arity.
Sassenrath wrote Amiga Logo before starting REBOL.
The square brackets aren't really analogous to Lisp's parentheses; REBOL / RED use parentheses for the same purpose, if you need them. The square brackets are more like square brackets in Factor or Joy; they are 'quotations' around a list of words (or other syntactic structures; basically they make a list that is not evaluated immediately).
>This is like the only programming language I could never learn.
Wait till you hear of Urbit and see this: https://developers.urbit.org/overview/nock
It's worth noting this work came from a prominent internet extremist. A generous interpretation would be that it is a high-effort troll.
I spent too long trying to learn this & hoon, not worth it ;_;
When I look at a programming language site, especially for a "new" language, I want a quick way to navigate to a reasonably sized decent code sample, ideally documented, showing off significant language features, idiomatic syntax and usage patterns etc...
Sites which do this well (just from the top of my head):
https://odin-lang.org/
immediate code sample visible
"See the Full Demo"
"See More Examples"
https://ziglang.org/
immediate code sample
scroll down a bit, "More Code Samples"
"Getting Started" Nope
"Documentation" Nope
"Official Documentation" link to github
https://github.com/red/docs/blob/master/en/SUMMARY.adoc
"Home"
merely a chronologically sorted blog
newest entry links to 50 line "script" by chance
showing off multi-monitor support
(doesn't seem like a super helpful sample)
?You can watch https://www.red-by-example.org/
But no one has bothered to write a complete manual like Carl did for Rebol, and the language is a partial implementation in Rebol which has a hybrid Rebol/Red syntax that must ultimately be bootstrapped in Red. In short, you have the scaffolding around it and if you are not a total fan or a dev of the project it is not even worth it.
So, REBOL and Red are basically Fexpr-based Lisps, right? They never describe themselves this way (instead using terms like definitional scoping, etc.), but it all just seems like a non-rigorous Fexpr based Lisp (almost like a light-weight version of vau-calculus of Kernel).
I don't think in Red a function can decide whether to evaluate its arguments or not. It's more like a Logo: functions have fixed arity, so you don't need to delimite the call, and lists ("blocks") are always quoted, so you need to explicitly evaluate them.
red-lang.org is blocked!
Phantom believes this website is malicious and unsafe to use.
This site has been flagged as part of a community-maintained database of known phishing websites and scams. If you believe the site has been flagged in error, please file an issue.
Ignore this warning, take me to https://www.red-lang.org/p/about.html anyway.Not very reliable, this Phantom thing.
ah, this is not about the Red Language that Intermetrics designed in 1977-79 to satisfy the Steelman requirements of the DoD's High Order Language Working Group... (the Green Language won and became known as Ada).
I thought maybe someone had put the DoD's Red language spec online.
And yes, someone has: https://iment.com/maida/computer/redref/
I haven’t looked at this in detail, but it seems they confuse “human-friendly syntax” with “absence of (<[{“.
The website looks like 2013 and much of the content is as well. There's a GitHub repo that I couldn't find from the website: https://github.com/red/red
The website links to GitHub with the usual logo, in the right hand column.
The website has posts from 2025:
https://www.red-lang.org/2025/04/multiple-monitors-support.h...
Unless you mean the theme, thats probably just a standard Google Blogger/Blogspot theme, which has been around for 25 years.
The repo seems to be alive and kicking.
I have tried Rebol out a little, multiple times over the years. it's a cool language. I like it.
I also got to know about Red early, followed it and tried it out for a bit.
but as others have said, that move to crypto, to fund the dev work and make the devs money, put me off for good. nothing wrong with making money, let them make plenty, I just didn't jive with crypto as a way of doing it.
sad about it going that route
I know asciidoc from red and erlang, it's a nice language. Not sure why it is not as popular as markdown.
There aren't many parser libraries for languages other than ruby. Its Ruby implementation, Asciidoctor, is considered as the reference implementation. However, it's being standardized and the situation will hopefully improve.
It's a little more complex, but I like it too. I've worked in teams that put all in-repo documentation in Asciidoc, it was really nice for adding in diagrams of complex systems and dependency trees.
I cant find some stuff from the docs. What i am wondering is:
For 'platforms' it notes for x86_64, "linux" and other operating systems.
is there a compiler option for this thing to make it spit out a 'freestanding' binary for the architectures it supports?
32 bit only
Which is a deal breaker for macOS users... unless they are still on Mojave.
red was terrible in 2018, and its terrible now - just tried to compile hello world and it takes 36 seconds
Go compiles massive codebases in that time. V can recompile itself probably 2-3x in that time.
I don't take any new language seriously unless it's memory safe, free of UB, able to interoperate with what already exists including optional shared libraries (because static linking the world every time in everything is memory and disk wasteful), and assists formal proofs of correctness. Otherwise, what already exists seems preferable for serious use and hobbies can remain fun distractions.
troll spotted
(2011,2013)
Seems the last release (alpha) was in 2015.
> Red’s ambitious goal is to build the world’s first full-stack language, a language you can use from system programming tasks, up to high-level scripting through DSL.
Pretty nonsensical statement. We have that for 50 years. Common Lisp, for example.
I’m right there with you. Modern languages have such a plethora of tooling available that DSLs and any API approaching a DSL have this massive gap unless they really embrace whatever patterns the host language’s tooling enables.
Not long ago, i had to work with a coworker’s mini language and function runner engine, which was basically a mini programming language. Except without a debugger or type checker or stack traces or any of the other million niceties we’d have had if we just used the host language to execute things ‘natively.’
That said, while the level of tooling for big languages goes up, the bar for creating yesteryear’s tooling is going down, with all the LSP tooling we have now, for example. Maybe someday we’ll get languages with tools where libraries have nice tooling without crazy dev effort, and then we’ll change our tune on DSLs.
I like the idea of DSL, but in real projects, I hate almost every DSL introduced by coworkers.
I've come to hate DSLs. With rare exception, almost every DSL has become a brittle subset of the parent language.
I heard that in Lisp every program becomes a DSL?
An API is just as much a DSL.
Kind of, except that a non-DSL API doesn't create any new syntax. Which means that you get to keep all sorts of quality-of-life tools like syntax highlighting and correctness checking in the editor, autoformatting, possibly some amount of linting, etc.
A few years ago I revisited Racket after a long hiatus, and that was maybe the biggest thing I noticed. I really don't like syntax macros as much as I did back in the day. Once I decide to use `define-syntax` I've then got to decide whether I also want to wade into dealing with also implementing a syntax colorer or an indenter as part of my #lang. And if I do decide to do that, then I've got a bunch more work, and am also probably committing to working in DrRacket (otherwise I'd rather stay in emacs) because that's the only editor that supports those features, and it just turns into a whole quagmire.
And it's arguably even worse outside of Racket, where I might have to implement a whole language server and editor plugin to accomplish the same.
Versus, if I can do what I need to do with a reasonably tidy API, then I can get those quality of life things without all the extra maintenance burden.
None of this was a big deal 20 years ago. My expectations were different back then, because I hadn't been spoiled by things like the language server protocol and everyone (finally) agreeing that autoformatting is a Good Thing.
Conversely, Ruby is often seen as facilitating DSL's, but none of it changes syntax, because the syntax as-is is flexible enough that redefining methods is sufficient. But everything still abides by the same syntactical rules.
The more orthogonal or flexible the language is, the less there tends to be a distinction between redefining syntactical elements and defining functions or methods.
Even without the new spiffs, I still don't see the point of DSLs. From where I sit, I see exactly zero problems where I think that new syntax is what I need to be able to write a solution.
I used to feel that way. I’m still not a convert, but now I’ve seen a lot more complexity papered over by a nice DSL.
Standard math syntax is a DSL. I understand math a lot more quickly than I understand the same thing written in 20 lines of code.
I think the language we use to express ourselves influence the quality of the product. If your language encapsulates complexity, then you can build more complicated things.
I’m not arguing in favor of specific (“pointless”) DSLs, but there’s a nice paper about making a video editing language in Racket [1] that makes a DSL seem pretty convincing.
[1]: https://www2.ccs.neu.edu/racket/pubs/icfp17-acf.pdf
TBH, I feel like regexes would be much easier to understand in a more literate form with standard syntax. Something like:
Where, in a real program, `domain` would be defined in a "standard library of constructions" that you can just import and re-use in more complicated regexes.Something like this can be implemented in any language with operator overloading, no DSL required. Without operator overloading, the syntax would be a bit more awkward, but still nicer than the current regexp madness.
Fair point, though I learned regexes a long time ago, so that they weren't on my "problems that I can solve with new syntax" list, but instead on the "syntax that's already there" list.
No, an API uses existing rules, but a DSL uses its own ad hoc rules.
GP is right. Don't make DSLs, make APIs, which are:
* More composable
* More reusable
* More simple to reason about
* More natively supported
* More portable
* More readable
* More maintainable
An API creates its own ad hoc rules too. They just don't change the grammar.
In languages where the grammar is sufficiently flexible, the distinction all but disappears, but even in languages where the grammar is rigid and API's stand out like a sore thumb, the API itself still creates a new rule-set that you need to learn.
You can choose to not call that a new language all you want, but the cognitive load is still there.
I've seen it. Sometimes a DSL is more readable than trying to shoehorn control flow into method calls (".then().catch()..."). Or see C#'s LINQ.
Yes, this reminds me of meta-programming in languages like Python, it's useful if you want to create a framework like Django, but if you work on products, chances are good you should not use it.
There are plenty of places where it makes more sense to use DSLs (or where they’re flat-out required). SQL and regex both spring to mind. Pretty much any HTML templating language is simpler to use than concatenation a bunch of strings together. JSX is usually easier read than directly calling React functions directly. A line of a shell script can be much nicer (and more portable) than 20 lines of a more general purpose language.
Those are things that spring to mind that I think are unequivocally DSLs, but if you’re willing to consider markup languages as DSLs, the list could get a lot longer.
I don't think of DSLs as strictly being embedded in another programming language. The term I would use for that is "eDSL", short for Embedded Domain Specific Language. See: https://wiki.haskell.org/Embedded_domain_specific_language
Martin Fowler on DSLs, including internal and external DSLs:
https://martinfowler.com/books/dsl.html
https://martinfowler.com/dsl.html
Also see:
https://en.m.wikipedia.org/wiki/Domain-specific_language
including the References section.
No, an API is a contract. Just like an object or a class or a structure is not a DSL. None of these modify the syntax or keywords of the language used to implement them, and only objects and classes actually have the ability to override operators.
Just grouping things together in a particular order and giving the group a name does not make a DSL.
The API creates a language just the same modifying syntax, by introducing new words with new meaning.
The point is that however you want to group it, the effect is the same: You introduce a whole new vocabulary that you need to learn the rules of.
this is a very important lesson. I remember the frustration of dealing with the Gradle and whatever was the name of the DSL used by Fastlane. Gradle especially kept changing so documentation was never really useful and there was zero help from the tooling
An API is an interface, metaprogramming is a technique for building such interfaces by treating code as data. They aren't interchangeable concepts.
Metaprogramming comes in handy when ordinary programming results in a lot of complex, hence unmaintainable, code or can't achieve something due to how the language is implemented. It can vastly simplify how you express application logic, e.g. when interfacing with foreign programming languages such as SQL or generating code from data.
Any sane metaprogramming regime allows you to do something like macro expansion, i.e. look at the code the metaprogramming is compiled into in the current context.