specifications VS treenotation.org

Notice that here I used a convention where names which end with "=" become XML attributes, whereas names which don't become children.

I have used the same convention here (except I don't bother with transforming names with spaces into camelCase): https://github.com/jevko/specifications/blob/master/easyjevk... to generate this HTML file: https://htmlpreview.github.io/?https://github.com/jevko/spec...

Now I intend to write specifications that codify conventions like this into different formats based on this fundamental syntax of square brackets.

It can be useful for all kinds of things. Its advantage is extreme simplicity and flexibility.

BTW, for clarity I have to say that the format that I used here: https://news.ycombinator.com/item?id=32995047 does a bit more transformations -- it actually sometimes treats whitespace as a separator (e.g. in `svg width[391]` space is a separator). That allows for extreme conciseness, but is not necessary and introduces complexity.

A plain Jevko parser simply turns your unicode sequence into a tree which has its fragments as leaves/labels.

No data types on that level, much like in XML.

Now above that level there is several ways to differentiate between them.

The simplest pragmatic way is a kind of type inference: if a text parses as a number, it's a number, if it's "true" or "false", it's a boolean. Otherwise it's a string. If you know the implicit schema of your data then this will be sufficient to get the job done.

Otherwise you employ a separate schema -- JC in particular has per-parser schemas anyway, so that's covered in this case.

Or you do "syntax-driven" data types, similar to JSON, e.g. strings start w/ "'".

Here is a shitty demo: https://jevko.github.io/interjevko.bundle.html

It shows schema inference from JSON and the schemaless (syntax-driven) flavor.

Jevko itself is stable and formally specified: https://github.com/jevko/specifications/blob/master/spec-sta...

It's very easy to write a parser in any language (I've written one in several) and from there start using it.

However, I am still very much working on specifications for formats above Jevko. I have some recent implementations of the simplest possible format which converts Jevko to arrays/objects/strings:

* https://github.com/jevko/easyjevko.lua

Thank you for your feedback. Can you clarify?

What is the "first page" that you are referring to?

Can you paste a link to it along with the broken examples link?

This Hacker News submission features the blog post under this URL:

https://djedr.github.io/posts/jevko-2022-02-22.html

Clearly, you are not talking about this page, as that contains multiple links rather than a singular link.

Perhaps you are talking about the specification which is here:

https://github.com/jevko/specifications/blob/master/spec-sta...

(linked from the blog post)

and here:

https://jevko.org/spec.html

(linked from jevko.org)

All three link to Jevko examples here:

https://github.com/jevko/examples

but all these examples links seem to be correct on my end.

I agree about the importance of examples, and I try to lead with them on jevko.org and jevko.github.io (which are the front pages of Jevko -- possibly I should merge them into one).

However a formal specification is not necessarily the place to put the leading examples.

This is also where the Subjevko rule is defined. It isn't quite introduced as "known knowledge" -- the purpose of a specification is to define the unknown, more or less from the ground up. This is also why specifications tend to get a little abstract. Jevko's spec is no exception. This should be in line with expectations of authors of tools such as parsers, validators, generators, or other kinds of processors, for which the spec is the authoritative reference.

It is not necessarily the best first place to look for explanation, if you are approaching from a more casual side.

I agree that from that side a clear picture of what Jevko is and how it can be used is still lacking. I certainly should add more examples and explain the concepts with analogies.

So I appreciate the essence of your advice and hope I'll manage to improve on that.

> concatenating them changes the label for [b] from "a" to "z\na", and perhaps more damningly, erases the whitespace before "z". But, since none of the alternative formats (except ndjson and I guess plain uninterpreted binary, ASCII, or Unicode) is closed under concatenation, maybe that's less important.

Yes, being closed under concatenation is a feature I was aiming for and it indeed does bring with it this issue.

Just something to have in mind when devising formats. A simple solution here is to disallow having anything other than whitespace in the suffix of a Jevko with > 0 children. Then, if a format converts these labels to keys in a map, trimming leading and trailing whitespace, there is no problem. This is how I did it here:

https://github.com/jevko/easyjevko.js

> I don't know if you saw the last time this topic came up I linked to https://ogdl.org/, which seems pretty close to a minimal rose-tree notation.

Yes, I've seen OGDL before. It's pretty nice. A similar one is https://treenotation.org/

I have experimented with indentation-based syntaxes myself, before settling on brackets.

I have found them to be problematic, at least because:

* For complex structures they become less compact.

* A grammar that correctly captures significant indentation can't really be written in pure BNF. The way OGDL does it is this:

  [12] space(n) ::= char_space*n ; where n is the equivalent number of spaces (can be 0)

This reminds me a bit of Breck Yunits' Tree Notation (https://treenotation.org/). Both seem to have a ~totalizing energy. Maybe some common cause. :)

Hi, I'm a programmer and I've used quite a few different languages in my career. I've never studied compilers or language design, however it has always interested me from afar. Also I've always had a strong preference for simple syntax, what sane person wouldn't? Anyway I've scanned over the https://treenotation.org/ site. I get the general gist, that this provides a tool to easily create languages that use tree notation. Unfortunately I still don't really understand how to use it. If there was tutorial that held your hand that would be really useful. I suspect there a large number of people like myself that would benefit from this. Perhaps at some point I'll role up my sleeves and do it myself, but I'm sure someone else could do a better job.

> The way to fix this trend would be to reimagine the presentation layer of the browser as something other than a stack of hacks over hypertext, but so far nobody seems to have a good solution.

About a decade ago I had the start of a Eureka moment on how to do this (back then — https://medium.com/space-net/spacenet-51aca95d49a2, nowadays https://treenotation.org/). It seems to me we've missed a sort of fundamental universal notation of the universe, which you can think of as "two-dimensional binary". I predict we will soon see a Cambrian Explosion of new formats and notations that are simpler and more interoperable with each other, and some will have the opportunity to build new great languages for rendering stacks.

Awesome app. Do you plan on using it for anything in particular? Or are you just creating it as a passion project. It's totally cool.

Learning about https://treenotation.org/ (linking this for other people, not for you, Breck :P), and I like what I see. My first impression was "Lisp, but with python indenting"

> We no longer need to store our data in error prone CSV, XML, or JSON. Tree Notation gives us a simpler, more powerful encoding for data with lots of new advanced features

This is the one thing I didn't understand! Tree notation seems equivalent to these. Like at a certain level, it's all just data. Now, the major benefit is that you're supposed to think differently about what you're doing when using tree notation. Would love to hear your opinion about this conjecture.

Lots of code examples here: https://jtree.treenotation.org/designer/

And the source for that homepage is here: https://github.com/treenotation/treenotation.org

Always open to PR!