OCaml Weekly News

There are new releases of these packages:

• Ptime POSIX time for OCaml, release notes, docs
• Mtime Monotonic time for OCaml, release notes, docs
• Qrc QR code encoder for OCaml, release notes, docs

See the individual release notes for details about the changes.

The library structure of Ptime and Mtime was changed to align it on the mythical library convention and make it for less surprising names (it used to make sense, it no longer does):

• The {M,P}time_clock modules are now in the {p,m}time.clock libraries as they should be. These libraries were also made to export the base {p,m}time library so that you can trim you requires when you use the clocks.
• The libraries {p,m}time.clock.os are deprecated. They now simply export {p,m}time.clock and warn on usage.

Best and a big thanks to my donors

Unicode 16.0.0 was released on September 10th. It adds 5185 new characters for a total of 154'998 characters.

If you are into retrocomputing or terminal graphics this may be your ultimate chance to find an odd character to make an effect among the 686 new symbols for legacy computing that are added – I'm hearing this may me be the last batch, the resource is finite! See the announcement page for links to all the other equally interesting additions.

If you are obsessed about deep linking into standard definitions, note that the normative core specification becomes a proper HTML document; rather than a bunch of PDF files or that 1400 pages hard-copy I once purchased for 5.0.0 circa 2007 :–). The neat result is that we can now precisely hyperlink to the normative definition of an OCaml Uchar.t value.

Accordingly these libraries had to be updated (aggregated, boring, release notes here)

• Uucd 16.0.0 Unicode character database decoder for OCaml, docs
• Uucp 16.0.0 Unicode character properties for OCaml, docs
• Uunf 16.0.0 Unicode text normalization for OCaml, docs
• Uuseg 16.0.0 Unicode text segmentation for OCaml, docs

Both Uucd and Uucp are incompatible releases sinces new block and script enumerants were added.

Other than that the minimal Unicode introduction and Unicode OCaml tips is still here and remember that despite the uninformed myths OCaml :heart: Unicode.

A big thanks for funding from the OCaml Software Foundation and from my faithful donors.

The demo presentation video is now online: https://watch.ocaml.org/w/peT3MdWjS1BYYMbowEJ1gv – thank you to everyone who joined and particularly the mentors, co-mentors and interns!

A big thank you also to Tarides and Jane Street for providing resources and funding to make this round possible. A reminder that today is the last day to sign up to the next round – Outreachy December 2024 Round!

FYI: For people like me who were on vacation or otherwise unavailable, the several hour Live Stream is still available.

The intro to the workshop and the first OCaml talk start at https://www.youtube.com/live/OuQqblCxJ2Y?t=2254s.

DkML 2.1.3 was released. The major changes are:

• Upgraded from opam 2.2.0 to opam 2.2.1.
• The ocaml/opam-repository tag was advanced to Sep 10, 2024.
• bugfix: dk Ml.Switch init was broken on Linux and macOS. DkML 2.1.2 had incorrectly pinned the dkml-host-abi and dkml-target-abi of the master DkML build machine. https://gitlab.com/dkml/distributions/dkml/-/issues/24
• Allow prereleases of Visual Studio; requested at https://gitlab.com/dkml/distributions/dkml/-/issues/23.

Upgrading is:

winget remove dkml # Ignore "exit code: 4294967295"
winget install dkml

The full release notes are at https://gitlab.com/dkml/distributions/dkml/-/releases/2.1.3.

I would like to announce the first release of store (docs), a library providing a snapshottable bag of mutable references, an efficient data-structure for back-tracking workloads.

To install it, type opam update && opam install store.

Store provides a simple API for capturing and restoring state as well as easy-to-use high-level wrappers to automatically rollback changes on failure (tentatively) or unconditionally (temporarily). It boasts almost-zero overhead when back-tracking is not used and best-in-class performance for back-tracking use cases.

The design and implementation of Store is described in the paper Snapshottable stores, which was given a Distinguished Paper award at this year's ICFP in Milan. As recognized by this award, the paper is well-written and easy to understand; please give it a read if you are interested in either back-tracking workloads or subtle data structure invariants!

I also want to give a shout-out to François Pottier's Monolith, which proved invaluable during the development of Store to find and diagnose subtle bugs.

Store was developed through collaboration between myself (Basile Clément) at OCamlPro and Gabriel Scherer at Inria, and the persistent interface was formally verified by Clément Allain and Alexandre Moine at Inria.

There's a new release of Tsdl, thin bindings to the C SDL library. See the release notes for details.

• Docs: online or odig doc tsdl
• Install: opam install tsdl

Daniel

A big thanks to my donors.

OCaml-css 0.2.0 is released and already available in opam (package css).

OCaml-css is a library to parse and print CSS. (docs)

Main changes are the introduction of property spaces and partial handling of nested rules.

Properties are now defined in spaces. A Css space is predefined, with some CSS properties, but you can define a new space with specific properties to use the CSS syntax for these properties in your application. (this is what is done in the to be not yet released 0.2.0 version of stk).

Nested style rules are now parsed and can be expanded. Nested @-rules are not handled yet.

I am happy to announce another release of DkCoder - a no-install OCaml-based scripting framework.

Major changes:

• Split out the Java-like packaging and security tools into the MlFront project: https://discuss.ocaml.org/t/ann-mlfront-a-java-like-package-system-for-ocaml/15072.
• The DkCoder and MlFront version numbers are now in sync with DkML version numbers. However, DkCoder is still alpha and there is at least one breaking change coming.
• Several third-party "Us" scripts are embedded and supported. (They are listed at bottom of this post).

Docs: The main doc page is https://diskuv.com/dksdk/coder/2024-intro-scripting/. But I don't yet have good reference docs. The samples below have been updated and are good ways to see what DkCoder can do (use the V2_1 branches):

• https://gitlab.com/diskuv/samples/dkcoder/DkHelloScript.git
• https://gitlab.com/diskuv/samples/devops/DkSubscribeWebhook.git
• https://gitlab.com/diskuv/samples/dkcoder/SanetteBogue.git

There are many bug fixes and new features. The full list is at https://github.com/diskuv/dkcoder/blob/1.0/CHANGES.md#2132 - all the sections from 0.4.0.1 to 2.1.3.2 (inclusive) are new.

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

• Upcoming OCaml Events (Sep 15, 2024 and onwards)
• Feature Parity Series: Compaction is Back!