OCaml Weekly News

The odoc team is delighted to announce the release of odoc 2.4.0. It mainly contains support for search engines. There are of course bugfixes and smaller new features.

Here are today’s meeting notes: https://github.com/ocaml-ppx/ppxlib/wiki/Dev-meeting-19-12-2023

>From next meeting on, I’ll make sure to only send one message on discuss per meeting containing both the agenda and a link to future meeting notes.

Have a nice new year everyone! :tada::)

Dear all,

My colleague @K_N managed to have half of the lab addicted to Advent of Code :sweat_smile:

This year, many problems involve grids, and it proved useful to have a tiny library to handle two-dimensional arrays. So here it is (and via opam):

• https://github.com/backtracking/grid
• documentation

Nothing sophisticated, and nothing you could not do with Array from the standard library, of course, but useful nonetheless.

Note: This is not a linear algebra library.

Happy hacking, Jean-Christophe

Dear OCamlers,

The series on ocaml.org tutorial updates continue. This time, the ocaml.org team has three drafts related to the module system in a single pull request. We want your feedback on it:

• GH PR: Update Modules and Functors Tutorials #1778
• Online drafts:
  • Modules — This is refresh of the previous version
  • Functors — This is mostly new material
  • Libraries With Dune — This is entirely new material

The target audience is developers learning OCaml. No functional programming knowledge is assumed. However, it comes after the “Get Started” series:

1. Installing OCaml
2. A Tour of OCaml
3. Your First OCaml Program

They also require the first two tutorials of the “Introduction” series as prerequisites:

1. Values and Functions
2. Basic Datatypes and Pattern Matching

As the previously announced drafts, these also contain overlooked issues. We want to make it better with your help.

Share your feedback on GitHub or here, but do not use the “Contribute” link at the bottom of the staging pages.

Hope it helps

I’m glad to announce the release of Esperanto (0.0.5). This release integrates the last release of Cosmopolitan 3.1.

The latter incorporates a great deal of work on the Cosmopolitan toolchain:

1. a modification of the GCC compilation so that code no longer needs to be patched to transform constants into variables
2. cross-compilation support for aarch64
3. support for Apple Silicon

This release introduces a change in the construction of the portable artifact from OCaml source code, which is explained here. More generally, the steps are:

• compilation to x86_64
• compilation to aarch64
• linking the two artifacts with apelink.

Currently, this version of Esperanto has been tested with bob, an OCaml file-sharing program. We have tested its portability on Debian, Ubuntu, Mac M1, FreeBSD and Windows. As we make clear in the description, Esperanto’s sole purpose is to assist in the distribution of software (rather than to provide a supportive environment for developers). We therefore advise you to use Docker (or related technology) to create your portable executable from your sources (bob has, for example, a GitHub CI that produces such an executable).

Of course, we’re planning to integrate with OCaml 5, since pthread support is now available in Cosmopolitan (it wasn’t at first). So we only support OCaml 4.14 and OCaml 4.13. We’re waiting for a review of another project which is preparing its transition to OCaml 5 (ocaml-solo5) before integrating it into Esperanto.

Finally, we would like to thank the robur.coop cooperative (which you can help) for giving us the freedom to maintain this project.

PS: Esperanto is still in [a release process]() (and not immediately available via OPAM), but the process should be completed in the next few days.

Hi all!

Just wanted to share some efforts to bring OCaml to the cultural heritage sector. So far I have built a web annotation server using Dream and Irmin https://github.com/nationalarchives/miiify but have some plans to continue the work.

The challenges for our digital services are mainly around scale and there is a growing interest around green computing. Inspired by the talk Hannes gave at CCC, it would be great to explore the benefits of MirageOS!

Hi folks :wave: just wanted to share a little library I put together to do color manipulation in Mint Tea. It’ll be used in the next release of Mint Tea, and allow us to do gradients and all sorts of nice color stuff:

This first release of colors:

• Introduces RGB, LRGB, XYZ, LUV, UV types
• Includes standard white reference point `d65`
• Supports Linearizing/Delinearizing RGB
• Includes conversions between ANSI, RGB, LRGB, XYZ, and LUV
• Has blending for LUV and RGB (via LUV) with configurable mixing
• Includes an ANSI to RGB color table

I’m hoping to keep it super small and in pure OCaml so we can use it for terminals but also other places like web, or other graphics settings.

You can read the full changelog here.

If you’re interested in contributing to any of these, look for open good first issues, and don’t hesitate to reach out on Discord/X: @leostera :slight_smile:

Happy hacking! :camel: :hand_with_index_finger_and_thumb_crossed:

I have a full article and repository at https://gitlab.com/diskuv/samples/merrychristmas2023#dksdk-merry-christmas-2023.

Short version … huge thanks to Oleg for his preprint paper Generating C: Heterogeneous metaprogramming system description. I’ve adapted it so it mostly works with PPX and without BER MetaOCaml (although I intend to switch to BER MetaOCaml at some point).

Typing real OCaml on your keyboard:

$ git clone https://gitlab.com/diskuv/samples/merrychristmas2023.git
$ cd merrychristmas2023
$ opam switch create . 4.14.1 # or on Windows: dkml init
$ opam install . utop --with-test --yes
$ opam exec -- dune utop
#require "metaquot.ppx";;
open DkSDKMetatype_Offshore;;
open Xmas2023;;
let sum_ar_staged =
  ( Lexing.dummy_pos,
    [%expr
      fun arr n ->
        let sum = ref 0 in
        for i = 0 to 3 do
          for j = i to min (i + 3) (n - 1) do
            sum := !sum + arr.(j)
          done
        done;
        !sum],
    Lexing.dummy_pos ) ;;

print_c "sum_ar" (module SumArConv) sum_ar_staged ;;

prints real C code:

int DkSDKMetatype_Offshore_sum_ar(int * const arr,int const n){
  int sum = 0;
  for (int i = 0; i < (1 + 3); i += 1)
    for (int j = i; j < (1 + min(i + 3,n - 1)); j += 1)
    sum = sum + (arr[j]);
  return sum;
}

Other languages are easy to add.

Merry Christmas! Jonah

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

• OCaml Survey: Developers’ Perception, Interest, and Perceived Barriers
• OCaml: Memory Safety and Beyond