Comment by wahern
18 hours ago
> Also hard not to feel like this is reaching hard to try and recreate xslt.
I was never a fan of XML, but XSLT was (is!) a killer redeeming feature of the ecosystem. And it's still widely supported in browsers! It was such a shame that XML caught on where it sucked--configuration, IPC, etc--but languished where it shined, as a markup language with an amazing transformation capability in XSLT.
I think where XSLT fell over was that it's a real DSL, and a declarative, pure, functional DSL at that. People like to talk a big game about DSLs, but inevitably they're simplistic syntactic exercises that don't actually abstract the underlying procedural semantics of popular host languages. When faced with a well-designed DSL that makes difficult tasks trivial... people can't be bothered to learn.
here on HN I dare to out myself as a DSSSL lover, the scheme based predecessor of xslt.
I still can't wrap my head around how the neat and clean dsssl syntax, a real programming language, was replaced by an xml notation for the same: for cuntional code and a framework. because semantically, that's what xslt is: a functional language with a framework, geared at transforming xml instances.
but that syntax... and of course a much inferior and more obscure language than scheme underneath dsssl.
[delayed]
I’m a big fan of XHTML (strictness is good) and feel like XSLT could be a great addition, but I hate the syntax. I’d love to build a Jinja to XSLT compiler one day.
I also have a simple playground for XSLT: https://xsltbin.ale.sh/
XSLT's weaknesses are the extension of its strengths. It's the first homoiconic, purely functional language that enjoyed widespread adoption among "normal" developers, not type theory wonks.
But XML's syntax sucks, and so inevitably does XSLT's, because XSLT is just XML. Were it s-expressions, the syntax could suck slightly less. It was (is!) a small price to generate XSLT using XSLT, which makes XSLT very powerful and expressive if you hold it right, almost like a Lisp. This saved me a few times around year 2000 or so.
Can you generate XSLT from s-expressions though? :thinking:
I barely used xslt, but as a fp head I wanted to try, the most confusing part to me were terminology / semantics / decoupling. Seemed like matching templates could be anywhere making difficult to understand the meaning of a script.
6 replies →
I wouldn't say it had widespread adoption. We used XSLT in my day job at the time to do client-side updates, even had a special SQL API that turned sql queries into XML automatically by naming the columns with a special syntax and it was virtually unheard of (2007?).
It was actually great when you got it, but the learning curve was so steep many developers couldn't use it effectively to begin with. For complex pages only certain developers could make changes or fix the bugs. Precisely because it was functional and most developers at the time really only understood imperative.
In fact, I remember the DailyWTF had a WTF about using XSLT as client-side transforms a few years later:
https://thedailywtf.com/articles/Sketchy-Skecherscom
But doing something like that was in fact so much faster than doing it in js, and when you groked it (deliberate throwback), it was so much simpler. I actually wrote a pivot table control in XSLT which completely blew away the performance of the pre-v8 javascript one. Pre-V8 javascript was so slow most developers wouldn't believe you now. A 10,000 iteration loop of even basic operations was often enough to cause IE6 to show a pop-up saying the page wasn't responding.
The pivot table in javascript would crash with just a few hundred lines of data, in XSLT it was instant with even 10,000s.
A really interesting use of XSLT on the web at the time was the WoW character viewer. You could view (and share) your character on Blizzard's website, with all their gear, skills, etc. It was blazingly fast for the time and it was all written in XSLT.
XSLT is not bad, but XML, unfortunately, is normally misused, so XSLT is tainted as it has to be a part of that misuse.
The true role of XML are grammar-based notations. These occur in two places: when a human gives data to a machine and when a machine produces data for a human. This is where XML is used despite its often mentioned shortcomings; for example, many notations to describe the user interface are based on XML. This is convenient, because user interfaces are created manually. (I am not mentioning text markup, it is well known.)
Yet XML was often used as a notation for machine-to-machine exchange. For example, the ONIX book description standard. Here data are moved between two computers, yet for some reason they have to form grammatically correct phrases according to a set of grammar rules. Computers do not need grammar. They do just fine with non-grammatical data, like a set of tables. It is way simpler for them; parsing or generating grammar, even explicit, is pure overhead for data exchange and is only necessary when data enters or leaves the computed pipeline.
So, to your examples: configuration in XML is actually fine, but IPC is not. Configuration is written by hand, IPC happens between machines. IPC specification, on the other hand, is also a good fit for XML.
That said, XML and thus XSLT has another flaw: it is way too verbose and has no good way to format it. Conciseness was an explicit no-goal but now we can say it was a mistake.
The XML abuse I've seen at work is truly horrifying. We use protobuf for most of our inter-service IPC, but for one particular team one of their customers demands the use of XML so that it can be run through some XSLT "security" filters, so they have to transform a fairly large protobuf object into XML, run it through said filters, and then convert it back to protobuf :( I weep every time I think about it.
It is probably impossible to find a tech stack that has not seen horrible abuse somewhere. :D
Granted, it did seem that XML got more heavily abused than some other options for a while. I am curious if that is just a by product of when it was introduced. That or just the general proliferation of how many front end developers we have. (I hate that I am pushing that to almost be a complaint. I certainly don't mean it that way.)
It's been a long number of years, but XUL (Mozilla/Firefox's UI layer) combined with XSLT was an incredible stack to build entire applications.
I regularly work with APIs in shell that return XML and XSLT is a goddamn super power. I adore it.
XSLT was cool.
XML needs another syntax that isn't so verbose. Sort of like how OWL has XML, Manchester, Functional, and Turtle syntaxes for the same data structures.
XSLT needs a Turtle-style syntax.
XML in general (the data structure, not the syntax) needs a Turtle-style syntax.
> but languished where it shined, as a markup language with an amazing transformation capability in XSLT
I choose to look at this a little differently.
An XML application using XSLT is so much better (faster load times, faster to write, easier to make correct) than a JavaScript application with a JSON api, that XML is basically a secret weapon.
I only care enough that it stays in browsers, but otherwise I'd prefer nobody know about it because it means less competition on things that matter (faster load times, faster to write, fewer bugs, etc). And I've got a half-baked JavaScript-based "renderer" I can finish in case some Google VP asshat goes looking for things to delete...
XSLT is just not a good language. Every single attempt of making XML executables (and there were many) failed badly, always for this one good reason.