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

Alan Schmitt
2025-02-04T12:05:35Z

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Hello

Here is the latest OCaml Weekly News, for the week of January 28 to
February 04, 2025.

Table of Contents
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Opam repository archive - clarification of the opam fields
Chúc mừng năm mới Ất Tỵ 2025!
Rewriting Slipshow in OCaml: The undo-able monad
Announcing climate.0.4.0
15th MirageOS retreat May 13th - 20th
Dune dev meeting
Other OCaml News
Old CWN

Opam repository archive - clarification of the opam fields
══════════════════════════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/opam-repository-archive-clarification-of-the-opam-fields/16050/1>

Hannes Mehnert announced
────────────────────────

Dear everyone,

we had further discussions about the semantics of
`x-maintenance-intent', and hope to clarify in this post. Also, we
adapted the policy which is in the opam-repository git repository:
<https://github.com/ocaml/opam-repository/blob/master/governance/policies/archiving.md>

x-maintenance-intent
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

We've had some further discussions on Phase 3 and the semantics of the
`x-maintenance-intent' field.

◊ Goal

Our aim is to be not disruptive for the common OCaml programmer or
user. The opam-repository supports (from February 1st on) OCaml 4.08
and greater. This means that if you install OCaml 4.08 you should be
able to install all the packages that have ever been released with
4.08 support.

The revised semantics of "(latest)" is "the latest version of this
package, so that every supported OCaml version will have an
installation candidate".

◊ Example

Let me give you an example, consider the package "basic" which
exists in three versions:
• basic.1.0.0 with the dependency "ocaml" {>= "4.05" & < "5"}
• basic.1.0.1 with the dependency "ocaml" {>= "4.08" & < "5"}
• basic.2.0.0 with the dependency "ocaml" {>= "4.14" & < "5"}

Here, if the `x-maintenance-intent: [ "(latest)" ]' is present, we
will only (try to) archive basic.1.0.0 – since 1.0.1 is needed for
OCaml 4.08 .. 4.13.

◊ Default value

The default value of `x-maintenance-intent' will for now be `"(any)"'
- so all versions are kept. In the future, we may change this default
to `"(latest)"', but will announce this ahead of the change with
plenty of time.

This default value is agreed on by the non-disruptive agreement to
cause the least trouble.

x-maintained
╌╌╌╌╌╌╌╌╌╌╌╌

In addition to the `x-maintenance-intent' - which covers the semantics
of all versions of an opam package, we support another field,
`x-maintained: BOOL'. This is an overwrite for a specific opam package
version, and allows to declare whether it is maintained or not.

It is useful in the setting where you've lots of pre-releases that are
no longer maintained and you like to state this without writing a
global intent for the opam package (e.g. for the OCaml compiler
packages, the alpha, beta, and rc versions). Here, `x-maintained:
false' is a nice setting. NB: earlier we proposed `flags: deprecated'
- but we stay away from the flags, since there may be packages that
are deprecated but still maintained (opam prints a warning if you
install a package with the deprecated flag).

If you have a private project and depend on a specific version of an
opam package, you can as well PR the `x-maintained: true' field for
that opam file (please specify when, who, and why). This will ensure
that this opam file stays in the opam repository.

Phase 3
╌╌╌╌╌╌╌

In Phase 3, we will consider all packages marked with
`x-maintenance-intent' (the versions not matching the intent) and
`x-maintained: false' to be archived.

We plan to ensure that (a) all supported OCaml versions will retain an
installation candidate (b) all reverse dependencies will still be
installable. As a note, if you have an availability condition (some
version will only work on some OS), we won't take that into
consideration – you will need to specify the `x-maintenance-intent' to
cover your versions.

Our plan is to publish the list of packages to be archived by February
15th on this discourse. It is likely we'll have candidate lists PRed
to the [opam-repository-archive] earlier. We have lots of ideas and
plans for CI systems to give feedback which opam versions are falling
into the maintenance intent when you open a PR to the opam-repository
(but we're not there yet).

[opam-repository-archive]
<https://github.com/ocaml/opam-repository-archive>

Future
╌╌╌╌╌╌

As noted above, the default value of `x-maintenance-intent' may change
in time. If this is decided, we will announce this with plenty of time
before.

Also, at some point in the future we will bump the OCaml lower bound
(from February 1st it is 4.08).

Action
╌╌╌╌╌╌

For the smooth shrinking of the opam-repository, please don't hesitate
to fill in your x-maintenance-intent (especially "(none)" and
"(latest)" are fine and safe choices).

If you want to contribute more, the opam-repository needs help for
triaging and merging PRs - why not become a maintainer? See the old
but still valid ['call for new opam-repository maintainers'] if you're
interested.

['call for new opam-repository maintainers']
<https://discuss.ocaml.org/t/call-for-new-opam-repository-maintainers/12041>

Chúc mừng năm mới Ất Tỵ 2025!
═════════════════════════════

Archive:
<https://discuss.ocaml.org/t/chuc-m-ng-nam-m-i-t-t-2025/16055/1>

sanette announced
─────────────────

Happy Vietnamese (and Chinese too) New Year!

It's the year of the snake, no its has nothing to do with `python',
but why not play [Snóke] ;)

Happy OCaml snaky year to all

<https://us1.discourse-cdn.com/flex020/uploads/ocaml/optimized/2X/7/724ead058962d131571f612fa8939f1847758c7e_2_1146x1000.png>

[Snóke] <https://github.com/sanette/snoke>

Rewriting Slipshow in OCaml: The undo-able monad
════════════════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/blog-rewriting-slipshow-in-ocaml-the-undo-able-monad/16069/1>

Paul-Elliot announced
─────────────────────

Hello OCamlers,

I have recently rewritten [Slipshow]'s engine from JavaScript to
OCaml. It turns out this rewriting was very satisfying, and many
niceties came out of it. I have written a blog post about a
specifically interesting one: the use of custom `let' operators with
the "undo-able" monad. I hope you enjoy the read!

The blog post: [How I fixed Slipshow's worst flaw using OCaml and a
monad].

[Slipshow] <https://github.com/panglesd/slipshow/>

[How I fixed Slipshow's worst flaw using OCaml and a monad]
<https://choum.net/panglesd/undo-monad/>

Announcing climate.0.4.0
════════════════════════

Archive:
<https://discuss.ocaml.org/t/announcing-climate-0-4-0/16084/1>

Steve Sherratt announced
────────────────────────

[Climate] is a declarative command-line parser for OCaml. This release
is mostly focused on improving `--help' messages and allowing the
colours of help messages to be configured.

[Climate] <https://github.com/gridbugs/climate>

Added
╌╌╌╌╌

• Allow help messages colours to be configured ([#7])
• Proof of concept of manpage generation (disabled in release as it's
very incomplete) ([#11])

[#7] <https://github.com/gridbugs/climate/pull/7>

[#11] <https://github.com/gridbugs/climate/pull/11>

Changed
╌╌╌╌╌╌╌

• Changed default help message colour scheme to be more colour-blind
readable
and more visible on light and dark terminals ([#7])
• Changed description of `--help' argument.

[#7] <https://github.com/gridbugs/climate/pull/7>

Fixes
╌╌╌╌╌

• Remove superfluous style reset escape sequences ([#7])
• Don't apply formatting to trailing spaces in argument names in help
messages ([#8])
• Print a readable error when the argument spec is invalid ([#10])

[#7] <https://github.com/gridbugs/climate/pull/7>

[#8] <https://github.com/gridbugs/climate/pull/8>

[#10] <https://github.com/gridbugs/climate/pull/10>

15th MirageOS retreat May 13th - 20th
═════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/ann-15th-mirageos-retreat-may-13th-20th/16085/1>

Hannes Mehnert announced
────────────────────────

Dear everybody,

we'll have another MirageOS retreat in May 2025 (13th - 20th). Happy
to see lots of old and new faces there.

Please jump to <https://retreat.mirageos.org> for further details, and
sign up and spread the word :)

Don't hesitate to ask questions in this topic.

Dune dev meeting
════════════════

Archive: <https://discuss.ocaml.org/t/ann-dune-dev-meeting/14994/22>

Etienne Marais announced
────────────────────────

Hi Dune enthusiasts :smile:,

We will hold the regular Dune Dev Meeting on **Wednesday, February,
5th at 9:00** CET. As usual, the session will be one hour long.

Whether you are a maintainer, a regular contributor, a new joiner or
just curious, you are welcome to join: these discussions are opened!
The goal of these meetings is to provide a place to discuss the
ongoing work together and synchronize with the Dune developers!
:ok_hand:

:calendar: Agenda
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

The agenda is available on the[ meeting dedicated page]. Feel free to
ask if you want to add more items in it.

[ meeting dedicated page]
<https://github.com/ocaml/dune/wiki/dev-meeting-2025-02-05>

:computer: Links
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

• Meeting link:[ zoom]
• Calendar event:[ google calendar]
• Wiki with information and previous notes:[ GitHub Wiki]

[ zoom]
<https://us06web.zoom.us/j/85096877776?pwd=cWNhU1dHQ1ZNSjZuOUZCQ0h2by9Udz09>

[ google calendar]
<https://calendar.google.com/calendar/embed?src=c_5cd698df6784e385b1cdcdc1dbca18c061faa96959a04781566d304dc9ec7319%40group.calendar.google.com>

[ GitHub Wiki] <https://github.com/ocaml/dune/wiki#dev-meetings>

Other OCaml News
════════════════

From the ocaml.org blog
───────────────────────

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

• [How we accidentally built a better build system for OCaml]
• [Tarides: 2024 in Review]

[the ocaml.org blog] <https://ocaml.org/blog/>

[How we accidentally built a better build system for OCaml]
<https://blog.janestreet.com/how-we-accidentally-built-a-better-build-system-for-ocaml-index/>

[Tarides: 2024 in Review]
<https://tarides.com/blog/2025-01-20-tarides-2024-in-review>

Old CWN
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If you happen to miss a CWN, you can [send me a message] and I'll mail
it to you, or go take a look at [the archive] or the [RSS feed of the
archives].

If you also wish to receive it every week by mail, you may subscribe
to the [caml-list].

[Alan Schmitt]

[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[caml-list] <https://sympa.inria.fr/sympa/info/caml-list>

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

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