[Caml-list] Attn: Development Editor, Latest OCaml Weekly News

[Alan Schmitt <alan.schmitt@polytechnique.org>]

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Hello

Here is the latest OCaml Weekly News, for the week of June 02 to 09,
2026.

Table of Contents
─────────────────

Richard Bird Distinguished Dissertation Award
Announcing Pyro Caml: A Continuous Profiler for OCaml
awso 0.9.1: Type-safe coverage for 400+ AWS APIs
OCaml 4.14.3 for Plan 9
Call for Talk Proposals @ OCaml Workshop 2026
Ahrefs Grant Program for OCaml
Old CWN


Richard Bird Distinguished Dissertation Award
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/richard-bird-distinguished-dissertation-award/18215/1>


François Pottier announced
──────────────────────────

  Hello fellow users of OCaml, If you or your students have defended a
  PhD in 2025 on a topic related to functional programming, then you may
  apply for the (new) Richard Bird Distinguished Dissertation
  Award. Announcement copied below.

  `==============================================================='

  CALL FOR NOMINATIONS

  Richard Bird Distinguished Dissertation Award 2025

  Deadline: 31st August 2026

  <http://tinyurl.com/jfp-bird-award>

  `==============================================================='

  OVERVIEW

  The Journal of Functional Programming is pleased to establish the
  Richard Bird Distinguished Dissertation Award, to recognise an
  outstanding PhD dissertation in functional programming.

  Richard Bird (1943-2022) was one of the leading figures in functional
  programming.  He was a Professor in Oxford, where he founded the
  Algebra of Programming group, and served as Director of the Computing
  Laboratory.  Richard is renowned for his many books and pearls on
  functional programming, which set a lasting standard for clear and
  elegant writing.  It seems fitting that an award be established in his
  name to further encourage these values in the field.

  The award includes a prize of £1,000.  Funding for the prize is
  supported by a generous donation from Richard himself to further the
  cause of functional programming.

  CRITERIA

  Eligible dissertations must have been completed in 2025.  Depending on
  the institution, this may be the date of the viva, corrections being
  approved, graduation ceremony, or otherwise.

  The award is open to all topics within the remit of JFP, with a
  particular emphasis on dissertations that reflect Richard's own values
  of clarity, simplicity and elegance.  For a dissertation to be
  considered for the award it should:

  • Reach a high standard of exposition;

  • Make a noteworthy contribution to the subject;

  • Place the results in the wider context of computer science.

  NOMINATIONS

  Please submit the following information to the award chair,
  graham.hutton@nottingham.ac.uk, by 31st August 2026:

  • Two letters of support, explaining why the dissertation should be
    considered for the award.  One letter should be from the
    advisor/supervisor, and one from an independent source with no
    conflict of interest with the candidate, such as an external
    examiner or other expert in the field.

  • A copy of the dissertation itself.

  AWARD COMMITTEE

  • Graham Hutton (chair), University of Nottingham
  • Matthew Flatt, University of Utah
  • Jeremy Gibbons, University of Oxford
  • François Pottier, INRIA
  • Wouter Swierstra, University of Utrecht
  • Ningning Xie, University of Toronto

  The JFP editors-in-chief serve as observers of the committee.

  `==============================================================='


Announcing Pyro Caml: A Continuous Profiler for OCaml
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announcing-pyro-caml-a-continuous-profiler-for-ocaml/18217/1>


Austin Theriault announced
──────────────────────────

  Hey y'all, last year I gave a [workshop] on observability at Fun
  OCaml, and a few folks asked me what was available for continuous
  profiling, and I wasn't aware of any solutions that supported OCaml
  directly.

  Since then I got the opportunity to work on one, and put it into use
  in production over at Semgrep, and now after battle testing it for a
  few months I'm happy to announce [Pyro Caml] is now available, and on
  [opam].

  I got a good excuse to use a lot of cool OCaml tools like ocaml-rs,
  the runtime event system, and memprof, so needless to say it was a
  bunch of fun to write this :slight_smile: . If you're interested in
  the details I have a blog post [here] covering them.

  Currently it only supports CPU profiling, but we're potentially going
  to add memory/gc profiling in the coming months. Enjoy!


[workshop]
<https://fun-ocaml.com/2025/ocaml-observability-with-opentelemetry/>

[Pyro Caml] <https://github.com/semgrep/pyro-caml>

[opam] <https://opam.ocaml.org/packages/pyro-caml/>

[here]
<https://semgrep.dev/blog/2026/announcing-pyro-caml-continuous-profiler-ocaml/>


awso 0.9.1: Type-safe coverage for 400+ AWS APIs
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-awso-0-9-1-type-safe-coverage-for-400-aws-apis/18220/1>


Michael Bacarella announced
───────────────────────────

  Greetings OCaml enjoyers,

  Have you been annoyed with terraform plan telling you 10 minutes later
  that you have a typo? Are you frustrated with how type-ambiguous your
  cloud is? (Abe Simpson shaking fist at cloud)

  Or, maybe you wish you could have AWS libraries inside an ecosystem
  you trust.

  Well, this release is for you!

  I'm happy to announce `awso', a comprehensive AWS library. This was
  forked from `https://github.com/solvuu/awsm', which was never released
  to opam. `awso' provides typed OCaml bindings to AWS services
  generated from botocore's service definitions, so the compiler catches
  the typos and shape mismatches.

  The `awso' repo: <https://github.com/mbacarella/ocaml-awso>


What's in the tin
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Typed clients for the full AWS surface area, generated from botocore
  1.43.9

  Four I/O backends:

  • `awso-eio' - Eio
  • `awso-async' — Async
  • `awso-lwt' — Lwt
  • `awso-sync' — Synchronous (blocking) over libcurl, for easy
    scripting and CLIs

  Also

  • `awso-cli': for fun, a kitchen-sink binary exposing every service as
    a composable subcommand, in the spirit of the Python aws CLI. (Ships
    as bytecode because linking \~400 native service libraries exceeds
    ARM64 executable size limits; yes really)

  Note: the AWS API is big. `opam install' may take awhile.


An example using Eio
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ (* ec2_describe_instances.ml *)
  │ module Ec2 = Awso_ec2_eio
  │ 
  │ let print_row a b c d = Printf.printf "%-16s  %-15s  %-39s  %-20s\n" a b c d
  │ 
  │ let print_instance instance =
  │   let name =
  │     Option.bind instance.Ec2.Instance.tags (fun tags ->
  │       List.find_map
  │         (function
  │           | { Ec2.Tag.key = Some "Name"; value = Some v } -> Some v
  │           | _ -> None)
  │         tags)
  │   in
  │   let instance_type =
  │     match instance.instanceType with
  │     | Some it -> Ec2.InstanceType.to_string it
  │     | None -> ""
  │   in
  │   print_row
  │     instance_type
  │     (Option.value instance.publicIpAddress ~default:"")
  │     (Option.value instance.ipv6Address ~default:"")
  │     (Option.value name ~default:"")
  │ ;;
  │ 
  │ let main env =
  │   let cfg = Awso_eio.Cfg.get_exn ~env () in
  │   match Ec2.describe_instances ~cfg (Ec2.DescribeInstancesRequest.make ()) with
  │   | Error e ->
  │     failwith
  │       (Printf.sprintf
  │          "Ec2.describe_instances: %s"
  │          (Yojson.Safe.to_string (Ec2.Ec2_error.to_json e)))
  │   | Ok { reservations; _ } -> (
  │     let instances =
  │       reservations
  │       |> Option.value ~default:[]
  │       |> List.concat_map (function
  │         | { Ec2.Reservation.instances = None; _ } -> []
  │         | { instances = Some instances; _ } -> instances)
  │     in
  │     match instances with
  │     | [] -> print_endline "no instances"
  │     | instances ->
  │       print_row "instance-type" "public ipv4" "public ipv6" "name";
  │       print_row
  │         (String.make 16 '-')
  │         (String.make 15 '-')
  │         (String.make 39 '-')
  │         (String.make 20 '-');
  │       List.iter print_instance instances)
  │ ;;
  │ 
  │ let () = Eio_main.run main
  └────


Major changes in the fork from awsm
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Replaced lightweight higher-kinded polymorphism with a functorized
    approach (architectural detail: end users don't need to use
    functors!)
  • Restructured into `aws/{eio,async,lwt,sync}/' so each backend ships
    only what it needs
  • Consolidated per-service opam packages into sub-libraries under each
    backend, on advice from the opam-repository crew. opam install
    awso-async pulls in every service binding as awso-async.
  • Transport errors now raise instead of polluting the Result type;
    only AWS-side errors stay in Result, matching Async convention
  • Dropped Jane Street Core from the non-Async runtimes via a small
    Jane_compat shim; Yojson.Safe.t everywhere instead of ad-hoc JSON;
    Base is still required for some rewriters and other tooling, but
    still much lighter weight than all of Core
  • Codegen is committed to the tree, so `opam install' doesn't drag
    \~25 build-time packages into your dependency cone
  • Output shapes treat required as advisory, because AWS itself
    routinely omits fields it marks required (looking at you,
    AccessDeniedException with no Message). Input shapes still respect
    it.
  • Various [working examples here]

  Minimum OCaml 5.3.0 to install from opam, OCaml 4.14 if you bump your
  stack limit before building.

  See CHANGES.md for the full list, and TODO.md for things known to
  still be rough.


[working examples here]
<https://github.com/mbacarella/ocaml-awso/tree/main/examples>


A bit of history
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  OCaml's AWS bindings have a lineage that predates this fork by years,
  with substantial development at Solvuu and collaboration from
  Tarides. Special thanks to Jane Street for their contributions along
  the way. It was open-sourced a while back and has sat quietly since.

  `awso' is an attempt to dust it off, bring it forward to current
  OCaml, and give it a home where the community can utilize it. Genuine
  thanks to everyone whose work this builds on! There's a lot of good
  engineering under the hood that deserves to keep running.


Help me get the credits right
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The code in the public solvuu repo was copy/pasted over from an
  internal repository, so the public git history doesn't reflect
  everyone who contributed. If you worked on any earlier version and
  want to be credited, please reach out.


Where it's going
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  0.9.1 is meant as a release-candidate-quality baseline ahead of a
  1.0.0. Near-term: working through TODO.md and more working
  examples. Issues and PRs welcome, particularly bug reports from real
  workloads.

  It works on 4.14 but you need to increase your stack size a bit to
  work around some non-TCO parts of the OCaml compiler. I'm trying to
  see if we can chunk things up differently to get it through opam-ci
  for OCaml 4.14.

  • Repo: <https://github.com/mbacarella/ocaml-awso>
  • opam: opam install awso-eio (or -lwt, or -async, or -sync)

  Bear with me while I spin some things in TODO.md off into GitHub
  issues. But I'm also curious to hear what might be missing from this
  release for you.


AI assistance disclosure
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Most of this work is directly coded by multiple humans over several
  years. A bulk of my own work in the project was back in 2022 porting
  it to ppxlib, making it work in OCaml 5 and growing the supported
  services from a handful to hundreds (bugfixes, missing support,
  working around botocore spec errors). Most of this work happened
  before the age of LLMs. Remember when "generated code" meant
  /generated by OCaml/? This guy remembers.

  I've since recruited Claude Code with Opus 4.7 for the push towards an
  opam release: mostly in refactoring, catching up on the latest
  botocore spec, and reducing the dependency cone. I hereby declare I
  understand and can answer for every line of code in awso.


Closing
╌╌╌╌╌╌╌

  I'm happy to hear feedback, especially on API ergonomics.

  <3 Michael


OCaml 4.14.3 for Plan 9
═══════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-14-3-for-plan-9/18223/1>


Eduardo Cavazos announced
─────────────────────────

  Hey y'all 🙋‍♂️

  I've been messing around with a port of OCaml 4.14.3 for Plan 9:

  <https://github.com/dharmatech/ocaml>

  The native compiler isn't supported yet. Just bytecode support, repl,
  etc.

  <https://us1.discourse-cdn.com/flex020/uploads/ocaml/original/2X/0/0b5d1dbf8b4ae9b3918143a6a790d19f422280bf.png>


Call for Talk Proposals @ OCaml Workshop 2026
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/call-for-talk-proposals-ocaml-workshop-2026/18192/2>


Continuing this thread, Sudha Parimala announced
────────────────────────────────────────────────

  The website is now live at
  <https://ocaml.org/ocaml-workshop-2026>. Please refer to it for the
  latest information!

  The submission deadline is roughly three weeks away! Please consider
  submitting your work.


Ahrefs Grant Program for OCaml
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ahrefs-grant-program-for-ocaml/17604/5>


Continuing this thread, Louis Roché announced
─────────────────────────────────────────────

  The recipient of the grants are:

  • [OCaml bindings for GTK 4] by Chris Armstrong
  • [LSP for menhir] by Federico Dal Pio Luogo
  • [Programmable Patterns for OCaml] by the team of Ningning Xie in the
    University of Toronto
  • [Update the WebAuthn OCaml library to specification level 3 from
    level 2 (2021)] by Robur
  • [Modernizing ocp-indent for OCaml 5.x] by ocamlpro
  • [Maintenance and Development of the Dream Web Framework] by
    Sebastian Willenbrink,
  • Introspectable OCaml, an OCaml variant (compile-time options) which
    provides an improved debugging and profiling experience, by
    [Shogan.ai] (Frederic Bour and Thomas Refis)


[OCaml bindings for GTK 4] <https://github.com/chris-armstrong/ocgtk>

[LSP for menhir] <https://github.com/dalps/menhir-lsp>

[Programmable Patterns for OCaml]
<https://github.com/ocaml/ocaml/issues/14627>

[Update the WebAuthn OCaml library to specification level 3 from level 2
(2021)] <https://github.com/robur-coop/webauthn/>

[Modernizing ocp-indent for OCaml 5.x]
<https://github.com/OCamlPro/ocp-indent>

[Maintenance and Development of the Dream Web Framework]
<https://github.com/camlworks/dream>

[Shogan.ai] <http://Shogan.ai>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
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  [Alan Schmitt]


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[Alan Schmitt] <https://alan.petitepomme.net/>


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