Specifications Alternatives

specifications reviews and mentions

• SVGs as Elm Code
  4 projects | news.ycombinator.com | 3 Nov 2022

  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.

• Jc – JSONifies the output of many CLI tools
  16 projects | news.ycombinator.com | 3 Nov 2022

  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

• Jevko: a minimal general-purpose syntax
  30 projects | news.ycombinator.com | 25 Oct 2022

  > What's happening here is parsing. `jevkoToHtml` is a kind of parser-transpiler which operates on a syntax tree, rather than a sequence of characters or tokens.

  That is obviously false. It's operating on a nested list of strings, whereby it's making a semantic decision whether a string in a certain position of a nested item in the structure ends in the = character.

  In other words the syntax is character-level. The strings themselves have syntax, which is made of characters. That's in the Jevko specification. Characters are the atoms in Jevko.

  The = character that the code is looking for is a %x3D element.

  It's right here: https://github.com/jevko/specifications/blob/master/draft-st...

  The = character is %x3D. An %x3D is Character. A Character is one of the kinds of Symbol (the other being Digraph). A Symbol is a constituent of Text. Text generates a Prefix or Suffix. A Suffix alone can be a Jevko due to this rule:

    Jevko ::= *Subjevko Suffix

  30 projects | news.ycombinator.com | 25 Oct 2022

  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.

  30 projects | news.ycombinator.com | 25 Oct 2022
• Syntax Design
  9 projects | news.ycombinator.com | 18 Oct 2022
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