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

Alan Schmitt
2022-04-12T08:10:48Z

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Hello

Here is the latest OCaml Weekly News, for the week of April 05 to 12,
2022.

Table of Contents
─────────────────

LexiFi is hiring!
Développeur principal à plein temps d'Alt-Ergo chez OCamlPro
Using an external JavaScript file in js_of_ocaml
diskuvbox: small set of cross-platform CLI tools
Old CWN

LexiFi is hiring!
═════════════════

Archive:
<https://discuss.ocaml.org/t/job-fulltime-internship-paris-lexifi-is-hiring/9648/1>

Alain Frisch announced
──────────────────────

📢 [LexiFi] is hiring!

✔️ Software Engineer (full-time): <https://lnkd.in/evhkxTg>

✔️ Software Development Internship: <https://lnkd.in/gb-bdDA9>

LexiFi is a software editor, based in Paris. We have been happily
using OCaml 🐪 for more than 20 years in our entire software stack,
from backend components to UI (web & native) front-end, and we
contribute back to the OCaml community (check out our blog post :
<https://www.lexifi.com/blog/ocaml/ocaml-open-source/>)

Don't hesitate to contact me directly if you want to learn more about
the positions before applying!

[LexiFi] <https://www.lexifi.com>

Développeur principal à plein temps d'Alt-Ergo chez OCamlPro
════════════════════════════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/job-fulltime-paris-developpeur-principal-a-plein-temps-dalt-ergo-chez-ocamlpro/9660/1>

Fabrice Le Fessant announced
────────────────────────────

Alt-Ergo est l'un des solveurs SMT les plus efficaces pour la
vérification formelle de code. Il est ainsi utilisé derrière des
ateliers tels que Why3, Frama-C et Spark. Initialement développé par
Sylvain Conchon au LRI, il est aujourd'hui maintenu par OCamlPro,
grâce aux financements du Club Alt-Ergo (AdaCore, Trust-in-Soft,
Thalès, MERCE, CEA List), à des contrats bilatéraux d'évolution et à
des projets collaboratifs.

OCamlPro souhaite aujourd'hui recruter un développeur principal à
temps plein pour Alt-Ergo, pour compléter son équipe méthodes
formelles et accélérer l'évolution d'Alt-Ergo. Disposant d'une
expérience dans les méthodes formelles, ses missions seront :

• de découvrir le projet Alt-Ergo et tous ses composants (prouveur,
interface graphique, etc.) et d'en comprendre le fonctionnement à
travers l'exploration du code et la lecture d'articles
scientifiques;
• d'élaborer la roadmap de maintenance évolutive d'Alt-Ergo, en
collaboration avec les membres du Club Alt-Ergo, et de proposer des
améliorations qui pourront être financées au travers de contrats
bilatéraux ou de projets collaboratifs;
• de participer avec l'équipe à la maintenance corrective d'Alt-Ergo
et de fournir du support aux membres du Club Alt-Ergo;
• de participer à l'encadrement de stages et de thèses CIFRE autour
d'Alt-Ergo et des solveurs SMT en général;
• de suivre l'actualité des solveurs SMTs et des travaux scientifiques
connexes, et de maintenir des collaborations avec les experts
académiques du domaine;

Intégré au sein de l'équipe Méthodes Formelles d'OCamlPro, il
bénéficiera de leur expérience et leur fera bénéficier de son
expertise croissante dans l'utilisation d'Alt-Ergo. Outre la
maintenance d'Alt-Ergo, l'équipe Méthodes Formelles d'OCamlPro
participe à diverses activités:

• Développement d'outils open-source pour les méthodes formelles, tels
que Dolmen, Matla, etc.
• Expertises sur WhyML, TLA, Coq, et autres langages de spécification
et de vérification;
• Certification de logiciels pour les Critères Communs (EAL6 et plus)
• Spécification et vérification formelle de smart contracts (Solidity,
etc.)

Les bureaux d'OCamlPro sont dans le 14ème arrondissement de Paris
(Alésia). L'entreprise est connue pour son équipe sympathique, son
excellence technique, sa productivité, ses valeurs et son éthique.

Si ce poste vous intéresse, n'hésitez pas à envoyer votre CV à:

contact@ocamlpro.com

Pour plus d'informations sur OCamlPro:

<https://www.ocamlpro.com/>

Pour plus d'informations sur Alt-Ergo:

<https://alt-ergo.ocamlpro.com/>

Pour plus d'informations sur le Club Alt-Ergo:

<https://www.ocamlpro.com/club-alt-ergo>

Using an external JavaScript file in js_of_ocaml
════════════════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/using-an-external-javascript-file-in-js-of-ocaml/9661/1>

John Whitington asked
─────────────────────

I am a beginner at both Javascript and `js_of_ocaml', so I may be
mixing up all sorts of mistakes and misconceptions here.

I have compiled up an existing project, my command line PDF tools,
using `js_of_ocaml', and all is well:

┌────
│ $ node cpdf.js -info hello.pdf
│ Encryption: Not encrypted
│ Permissions:
│ Linearized: false
│ Version: 1.1
│ Pages: 1
└────

Like magic! But I had to comment out the parts of my code which use
external C code of course - that is zlib and some encryption
primitives. So now I wish to bind javascript libraries for those. I am
experimenting with a simple library of my own, first, which is given
on the command line to `js_of_ocaml' as `foomod.js':

┌────
│ foo = 42;
└────

I can get to this global variable easily from OCaml:

┌────
│ let foo = Js.Unsafe.global##.foo
└────

But now I want to do things better, and I change `foomod.js' to:

┌────
│ exports.foo = 42;
└────

How can I get to that? Giving `foomod.js' on the `js_of_ocaml' command
line includes the contents of `foomod.js' in some way, but does not
contain the string `foomod', so I'm not sure how to get to the
foomod's variables and functions. How to I access them? In the node
REPL, I can simply do:

┌────
│ > foomod = require('./foomod.js');
│ { foo; 42 }
│ > foomod.foo;
│ 42
└────

I have read the `js_of_ocaml' help page on how to bind JS modules:

<https://ocsigen.org/js_of_ocaml/latest/manual/bindings>

I imagine if I could get over this hump, all the rest of the
information I need will be there.

Nicolás Ojeda Bär replied
─────────────────────────

Not exactly what you asked, but if you just want to provide a JS
version of some C primitive

┌────
│ external foo : unit -> int = "caml_foo"
└────

you can do this by writing the following in your `.js' file:

┌────
│ //Provides: caml_foo
│ function caml_foo() {
│ return 42;
│ }
└────

Then `js_of_ocaml' will automatically replace calls to the external
function by a call to its JS implementation.

This is the same mechanism used by `js_of_ocaml' to implement its own
JS version of the OCaml runtime, see eg

<https://github.com/ocsigen/js_of_ocaml/blob/3850a67b1cb00cfd2ee4399cf1e2948062884b92/runtime/bigarray.js#L328-L335>

diskuvbox: small set of cross-platform CLI tools
════════════════════════════════════════════════

Archive:
<https://discuss.ocaml.org/t/ann-diskuvbox-small-set-of-cross-platform-cli-tools/9663/1>

jbeckford announced
───────────────────

*TLDR*:
┌────
│ $ opam update
│ $ opam install diskuvbox
│
│ $ diskuvbox copy-dir --mode 755 src1/ src2/ dest/
│ $ diskuvbox copy-file --mode 400 src/a dest/b
│ $ diskuvbox copy-file-into src1/a src2/b dest/
│ $ diskuvbox touch-file x/y/z
│
│ $ diskuvbox find-up . _build
│ Z:/source/_build
│
│ $ diskuvbox tree --max-depth 2 --encoding=UTF-8 .
│ .
│ ├── CHANGES.md
│ ├── README.md
│ ├── _build/
│ │ ├── default/
│ │ ├── install/
│ │ └── log
└────

*Problem*: When writing cram tests, Dune rules and Opam build steps,
often we default to using GNU binaries (`/usr/bin/*') available on
Linux (ex. `/usr/bin/cp -R'). Unfortunately these commands rarely work
on Windows, and as a consequence Windows OCaml developers are forced
to maintain Cygwin or MSYS2 installations to get GNU tooling.

*Solution*: Provide some of the same functionality for Windows and
macOS that the GNU binaries in `/usr/bin/*' do in Linux.

`diskuvbox' is a single binary that today provides an analog for a
very small number of binaries that I have needed in the Diskuv Windows
OCaml distribution. It is liberally licensed under Apache v2.0. *With
your PRs it could emulate much more!*

`diskuvbox' has CI testing for Windows, macOS and Linux. Usage and
help are available in the diskuvbox README:
<https://github.com/diskuv/diskuvbox#diskuv-box>

*`diskuvbox' also has a OCaml library, but consider the API unstable
until version 1.0.*

Alternatives:
• There are some shell scripting tools like [shexp] and [feather] that
give you POSIX pipes in OCaml-friendly syntax. I feel these
complement Diskuv Box.
• Dune exposes `(copy)' to copy a file in Dune rules; theoretically
more operations could be added.

Internally `diskuvbox' is a wrapper on the excellent [bos - Basic OS
interaction] library.

[shexp] <https://github.com/janestreet/shexp>

[feather] <https://github.com/charlesetc/feather>

[bos - Basic OS interaction]
<https://erratique.ch/software/bos/doc/Bos/index.html>

Acknowledgements
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

The first implementations of Diskuv Box were implemented with the
assistance of the [OCaml Software Foundation (OCSF)], a sub-foundation
of the [INRIA Foundation].

Two OCaml libraries ([bos] and [cmdliner]) are essential to Diskuv
Box; these libraries were created by [Daniel Bünzli] (@dbuenzli) .

[OCaml Software Foundation (OCSF)] <http://ocaml-sf.org>

[INRIA Foundation] <https://www.inria.fr>

[bos] <https://erratique.ch/software/bos>

[cmdliner] <https://erratique.ch/software/cmdliner>

[Daniel Bünzli] <https://erratique.ch/profile>

Examples
╌╌╌╌╌╌╌╌

The following are examples that have been condensed from the
[diskuvbox README.md] …

[diskuvbox README.md] <https://github.com/diskuv/diskuvbox#diskuv-box>

Using in Dune cram tests
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

┌────
│ $ install -d a/b/c/d/e/f
│ $ install -d a/b2/c2/d2/e2/f2
│ $ install -d a/b2/c3/d3/e3/f3
│ $ install -d a/b2/c3/d4/e4/f4
│ $ install -d a/b2/c3/d4/e5/f5
│ $ install -d a/b2/c3/d4/e5/f6
│ $ touch a/b/x
│ $ touch a/b/c/y
│ $ touch a/b/c/d/z
│
│ $ diskuvbox tree a --max-depth 10 --encoding UTF-8
│ a
│ ├── b/
│ │ ├── c/
│ │ │ ├── d/
│ │ │ │ ├── e/
│ │ │ │ │ └── f/
│ │ │ │ └── z
│ │ │ └── y
│ │ └── x
│ └── b2/
│ ├── c2/
│ │ └── d2/
│ │ └── e2/
│ │ └── f2/
│ └── c3/
│ ├── d3/
│ │ └── e3/
│ │ └── f3/
│ └── d4/
│ ├── e4/
│ │ └── f4/
│ └── e5/
│ ├── f5/
│ └── f6/
└────

Using in Opam `build' steps
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

┌────
│ build: [
│ ["diskuvbox" "copy-file-into" "assets/icon.png" "assets/public.gpg" "%{_:share}%"]
│ ]
└────

Using in Dune rules
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

┌────
│ (rule
│ (targets diskuvbox.corrected.ml diskuvbox.corrected.mli)
│ (deps
│ (:license %{project_root}/etc/license-header.txt)
│ (:conf %{project_root}/etc/headache.conf))
│ (action
│ (progn
│ (run diskuvbox copy-file -m 644 diskuvbox.ml diskuvbox.corrected.ml)
│ (run diskuvbox copy-file -m 644 diskuvbox.mli diskuvbox.corrected.mli)
│ (run headache -h %{license} -c %{conf} %{targets})
│ (run ocamlformat --inplace --disable-conf-files --enable-outside-detected-project %{targets}))))
└────

Old CWN
═══════

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
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[online].

[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>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

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

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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.