OCaml Weekly News

Third time the charm. OCANNL 0.3.3 is out now. I might need to change the name of the project, because of the lint warnings: Possible name collision with packages 'OCADml', 'ocal', 'ocaml'?

Repo at https://github.com/dangdennis/rwo-eio/blob/main/lib/rwo_eio.ml

I was inspired by Taride's Make an Eio version of the Async examples in Real World OCaml to translate the Async examples to eio to test out eio's concurrency story. Warning, it's a rough translation. I hardly know OCaml and eio as well as I know my day-job languages :smile: .

There are still a few examples I haven't figured out.

1. I don't know how to implement copy_blocks. In this section, the example uses an intermediate buffer of some sorts to then copy from reader to writer. For now, I've left that intermediate buffer out.
2. I can't find an interrupt option in cohttp-eio as well as choice and choose. The book explains that cohttp-async can cancel http requests via an interrupt (see section).
3. For log_delays, I have yet to solve how to await my own every ticker such that I can await its completion and then log the timer at the end.

Here's a blog post about how we have been using property-based testing to test OCaml 5: https://tarides.com/blog/2024-04-24-under-the-hood-developing-multicore-property-based-tests-for-ocaml-5/

Here's another one of our heads up about our latest blog release!

Today's topic is about an unintentionally hidden feature of the OCaml dev environmment: backtraces on uncaught exception!

We believe this will be old news to the veteran OCaml devs but could be of much use to the newer Cameleers out there!

Hopefully, you will learn a thing or two from reading this short article, we welcome all feedback in this very thread, thank you for reading!

Do you use OCaml on Windows? We want to hear from you! Participate in our user survey to share your experiences with the OCaml development environment on Windows. Your feedback is important in helping us understand the current pain points and identify areas for improvement. Whether you're a seasoned OCaml developer or just starting out, your input can make a significant difference.

Please sign up here https://forms.gle/SxRvNaEZXgedxrnR9, and we'll reach out to you.

I'm glad to announce the release of graphql_jsoo_client.

This is the client side implementation of the GraphQL over WebSocket Protocol. It is mainly intended for use with Dream, which implements the server side. This library supports writing client code in Ocaml, that will run in the browser.

It can be found here.

[ANN] dream-html 3.4.1

Add 'livereload' support ie automatically reloading the page in the browser when the Dream server restarts. Useful to run with dune's watch mode for a fast dev cycle.

This is adapted from Dream's own livereload middleware but with a slightly different approach. Full details in the module documentation: https://yawaramin.github.io/dream-html/dream-html/Dream_html/Livereload/

Why reimplement this? It seems that Dream's built-in livereload needs to parse the HTML markup, find its head tag, and dynamically inject the reloader script inside. Since parsing HTML can be pretty tricky and potentially buggy, I decided to manually add the script in the head tag as a strong-typed dream-html node:

head [] [
  ...
  Livereload.script;
  ...
]

I'm happy to announce the second release of DkCoder, an OCaml scripting tool.

The first release was about install ease: a couple clicks and four (4) minutes later you and your Windows and macOS users can start scripting. All users, including glibc-based Linux desktop users, can also use their Unix shells or Windows PowerShell. OCaml does not need to be pre-installed. Just copy and paste two lines (you'll see some in this post) and your script is running and your project is editable with OCaml LSP.

This second release is about technical ease. The three "big" ideas in this release are:

• You don't write build files. If that sounds like /bin/sh that is intentional.
• Almost every OCaml file is a script you can run. If that sounds like how Python scripts are almost indistinguishable from Python modules, that is intentional.
• Almost every OCaml file can be referenced with a fully-qualified name. If that sounds like Java packages that is intentional.

Here are some examples:

1. (one of my own scripts) The incomplete but growing DkCoder documentation is written in a script: https://diskuv.com/dksdk/coder/2024-intro-scripting/. The documentation is a side-effect of running tests.

   In a Unix shell or in PowerShell, the following will a) run tests using tezt, b) collect outputs, c) generate HTML documentation, and then d) serve the doc page on a tiny_httpd webserver for a quick preview:

   git clone --branch V0_2 https://gitlab.com/diskuv/samples/dkcoder/DkHelloScript.git
   
   ./DkHelloScript/dk DkRun_V0_2.Run -- DkHelloScript_Std.Y33Article --serve
   

   The following will print mixed Markdown/HTML that I can render and publish with a static site generator to a website:

   ./DkHelloScript/dk DkRun_V0_2.Run -- DkHelloScript_Std.Y33Article --doc --doc-format markdown
   

2. (someone else's) The Bogue demo game Snoke written by @sanette was "ported" to DkCoder. The port did not change a single line of the original code. I did re-arrange the directory structure (recall that there is a Java-like package mechanism underneath DkCoder) and I did add an extra .ml file. Run:

   git clone --branch V0_2 https://gitlab.com/diskuv/samples/dkcoder/SanetteBogue.git
   
   ./SanetteBogue/dk DkRun_V0_2.Run -- SanetteBogue_Snoke.Snoke
   

The remaining items for DkCoder before a 1.x release: auto-downloading remote libraries (mostly done), meta/codegen tools (in progress), conditional compilation (in design), and a security policy (in design).

But right now DkCoder is at a reasonable enough point that I can now recommend using it for your own scripts. With the usual caveats that this is a 0.x release.

I'd like some feedback, especially on pain points and missing must-have features.

I'm happy to announce the release of Ocaml-protoc-plugin version 6.1.0 Ocaml-protoc-pluginis a plugin for google's protobuf compiler (protoc) that generates an idomatic ocaml mapping and (de-)serialization functions based on .proto files. The library aims to be 100% compliant implementation of the protobuf specification.

The 6.1.0 (and 6.0.0) release introduces Json serialization and deserialization based on protobuffers guidelines and the ability to copy comments from .proto into ocaml generated code for improved documentation as well as numerous bug fixes and other improvements.

Full changelog since release 5.0.0

Here are links from many OCaml blogs aggregated at the ocaml.org blog.

• OCaml Backtraces on Uncaught Exceptions
• Under the Hood: Developing Multicore Property-Based Tests for OCaml 5