FAWK: LLMs can write a language interpreter

I've been working on my own web app DSL, with most of the typing done by Claude Code, eg,

  GET /hello/:world
    |> jq: `{ world: .params.world }`
    |> handlebars: `<p>hello, {{world}}</p>`
  
  describe "hello, world"
    it "calls the route"
      when calling GET /hello/world
      then status is 200
      and output equals `<p>hello, world</p>`

Here's a WIP article about the DSL:

https://williamcotton.com/articles/introducing-web-pipe

And the DSL itself (written in Rust):

https://github.com/williamcotton/webpipe

And an LSP for the language:

https://github.com/williamcotton/webpipe-lsp

And of course my blog is built on top of Web Pipe:

https://github.com/williamcotton/williamcotton.com/blob/mast...

It is absolutely amazing that a solo developer (with a demanding job, kids, etc) with just some spare hours here and there can write all of this with the help of these tools.

That is impressive, but it also looks like a babelfish language. The |> seems to have been inspired by Elixir? But this is like a mish-mash of javascript-like entities; and then Rust is also used? It also seems rather verbose. I mean it's great that it did not require a lot of effort, but why would people favour this over less verbose DSL?

> babelfish language

Yes, exactly! It's more akin to a bash pipeline, but instead of plain text flowing through sed/grep/awk/perl it uses json flowing through jq/lua/handlebars.

> The |> seems to have been inspired by Elixir

For me, F#!

> and then Rust is also used

Rust is what the runtime is written in.

> It also seems rather verbose.

IMO, it's rather terse, especially because it is more of a configuration of a web application runtime.

> why would people favour this

I dunno why anyone would use this but it's just plain fun to write your own blog in your own DSL!

The BDD-style testing framework being part of the language itself does allow for some pretty interesting features for a language server, eg, the LSP knows if a route that is trying to be tested has been defined. So who knows, maybe someone finds parts of it inspiring.