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OCaml Planet

The OCaml Planet aggregates various blogs from the OCaml community. If you would like to be added, read the Planet syndication HOWTO.

976 blog posts are available. You can read the 30 more recent ones below or view older ones.

opam 2.0.0 release and repository upgrade — OCamlPro, Sep 19, 2018

We are happy to announce the final release of opam 2.0.0.

A few weeks ago, we released a last release candidate to be later promoted to 2.0.0, synchronised with the opam package repository upgrade.

You are encouraged to update as soon as you see fit, to continue to get package updates: opam 2.0.0 supports the older formats, and 1.2.2 will no longer get regular updates. See the Upgrade Guide for details about the new features and changes.

The website opam.ocaml.org has been updated, with the full…


Continuous Benchmarking & Call for Benchmarks — KC Sivaramakrishnan, Sep 13, 2018

Over the past few weeks, at OCaml Labs, we’ve deployed continuous benchmarking infrastructure for Multicore OCaml. Live results are available at http://ocamllabs.io/multicore. Continuous benchmarking has already enabled us to make informed decisions about the impact of our changes, and should come in handy over the next few months where we polish off and tune the multicore runtime.

Currently, the benchmarks are all single-threaded and run on x86-64. Our current aim is to quantify the perfor…


Full Time: Compiler Engineer at Jane Street in New York & London — GitHub Jobs, Aug 30, 2018

Jane Street is a proprietary quantitative trading firm, focusing primarily on trading equities and equity derivatives. We use innovative technology, a scientific approach, and a deep understanding of markets to stay successful in our highly competitive field. We operate around the clock and around the globe, employing over 500 people in offices in New York, London and Hong Kong.

The markets in which we trade change rapidly, but our intellectual approach changes faster still. Every day, we have …


Full Time: Software Developer (Functional Programming) at Jane Street in New York, NY; London, UK; Hong Kong — GitHub Jobs, Aug 30, 2018

Software Developer

Jane Street is a proprietary quantitative trading firm, focusing primarily on trading equities and equity derivatives. We use innovative technology, a scientific approach, and a deep understanding of markets to stay successful in our highly competitive field. We operate around the clock and around the globe, employing over 500 people in offices in New York, London and Hong Kong.

The markets in which we trade change rapidly, but our intellectual approach changes faster still…


How to implement type theory in an hour — Andrej Bauer, Aug 25, 2018

I was purging the disk on my laptop of large files and found a video lecture which I forgot to publish. Here it is with some delay. I lectured on how to implement type theory at the School and Workshop on Univalent Mathematics in December 2017, at the University of Birmingham (UK).

You may watch the video and visit the accompanying GitHub repository spartan-type-theory.

Full Time: Lead Developer at HubTran in Chicago, Cincinnati, Remote — GitHub Jobs, Aug 22, 2018

Reporting directly to the CTO, you'll be a key member of our growing development team. Within the first six months you will be responsible for leading the development in one of our business segments. You will work closely with our commercial team, our end users, and our CTO to define and prioritize new features.

At Hubtran, you will join a team that:

  • Has experience. The majority of our developers have more than 10 years of professional experience. One has published a book with the Pragmatic P…

Ann: A new ppx for tyre and new version of ppx_regexp | Drup's thingies — Gabriel Radanne, Aug 21, 2018

Some times ago, I released Tyre, a library for Typed Regular Expressions that allows matching, printing and routing. While many people expressed interest, the syntax was (rightfully) considered too obtuse for practical usage. Thanks to Petter A. ‘paurkedal’ Urkedal, this should now be fixed!

Not-learning is a skill too — Gaius Hammond, Jul 29, 2018

To be successful in tech, it’s well known that you must keep your skills up to date. The onus is on each individual to do this, no-one will do it for you, and companies that provide ongoing personal development are few and far between. Many companies would rather “remix our skills”, which means laying off workers with one skill (on statutory minimum terms) and hiring people with the new skill. Which is short-termist in the extreme; the new workers are no better than the old, th…


opam 2.0.0 RC4-final is out! — OCamlPro, Jul 26, 2018

We are happy to announce the opam 2.0.0 final release candidate! 🍾

This release features a few bugfixes over Release Candidate 3. It will be promoted to 2.0.0 proper within a few weeks, when the official repository format switches from 1.2.0 to 2.0.0. After that date, updates to the 1.2.0 repository may become limited, as new features are getting used in packages.

It is safe to update as soon as you see fit, since opam 2.0.0 supports the older formats. See the Upgrade Guide for details about the …


frama-clang 0.0.6, compatible with Frama-C 17 Chlorine is out. Download ithere. — Frama-C, Jul 23, 2018

Algebraic effects and handlers at OPLSS 2018 — Andrej Bauer, Jul 22, 2018

I have had the honor to lecture at the Oregon Programming Language Summer School 2018 on the topic of algebraic effects and handlers. The notes, materials and the lectures are available online:

I gave four lectures which started with the mathematics of algebraic theories, explained how they can be used to model computational effects, how we make a programming langu…


OCamlPro’s Tezos block explorer TzScan’s last updates — OCamlPro, Jul 20, 2018

OCamlPro is pleased to announce the latest update of TZScan (http://tzscan.io), its Tezos block explorer to ease the use of the Tezos network. TzScan is now ready for the protocol update scheduled for tomorrow. In addition to some minor bugfixes, the main novelties are:


OCaml 4.07.0 released — Caml INRIA, Jul 10, 2018

Coq 8.8.1 is out — Coq, Jul 09, 2018

The 8.8.1 release of Coq is available.

It includes four critical bug fixes, many other bug fixes, documentation improvements and user message improvements.

For details, see CHANGES and the 8.8.1 milestone. Feedback and bug reports are extremely welcome.

Bucket Sort — Shayne Fletcher, Jun 10, 2018

Bucket Sort

Bucket sort assumes input generated by a random process that distributes elements uniformly over the interval [0, 1).

The idea of bucket sort is to divide [0, 1) into n equal-sized subintervals or buckets, and then distribute the n input numbers into the buckets. To produce the output, sort the numbers in each bucket and then go through the buckets in order. Sorting a bucket can be done with insertion sort.

let rec insert x = function
| [] -> [x]
| h :: tl as ls ->
if x <…

Frama-C 17 - Chlorine is out. Download ithere. — Frama-C, May 31, 2018

An OCaml quine | Drup's thingies — Gabriel Radanne, May 30, 2018

(fun x -> Printf.printf "%s %S" x x) "(fun x -> Printf.printf \"%s %S\" x x)"

opam 2.0.0 Release Candidate 2 is out! — OCamlPro, May 22, 2018

We are pleased to announce the release of a second release candidate for OPAM 2.0.0.

This new version brings us very close to a final 2.0.0 release, and in addition to many fixes, features big performance enhancements over the RC1.

Among the new features, we have squeezed in full sandboxing of package commands for both Linux and Mac OS, to protect our users from any misbehaving scripts.

NOTE: if upgrading manually from 2.0.0~rc, you need to run opam init --reinit -ni to enable sandboxing.

The ne…


simpl is less annoying than you think — GaGallium (Nathanaël Courant, Armaël Guéneau), May 22, 2018

In this blogpost we find out that it is possible to tweak the behavior of the Coq simpl tactic. We find it particularly useful when dealing with arithmetic goals on Z.

We just discovered an answer to a longstanding annoyance we faced when dealing with arithmetic Coq goals. Consider the following Coq goal, using integers on Z:

Require Import ZArith.
Open Scope Z_scope.

Goal forall a, 2 * a = 0 * a + a * 2.
  intros. simpl.

We call the simpl tactic to simplify 0 * a + ... into .... Unfort…


Dijkstra's algorithm — Shayne Fletcher, May 20, 2018

Shortest Path

This article assumes familiarity with Dijkstra's shortest path algorithm. For a refresher, see [1]. The code assumes open Core is in effect and is online here.

The first part of the program organizes our thoughts about what we are setting out to compute. The signature summarizes the notion (for our purposes) of a graph definition in modular form. A module implementing this signature defines a type vertex_t for vertices, a type t for graphs and type extern_t


Ann: Regenerate | Drup's thingies — Gabriel Radanne, May 08, 2018

I’m happy to announce the release of Regenerate, a library, tool and website to generate test cases for regular expression engines.

Release of Alt-Ergo 2.2.0 — OCamlPro, Apr 23, 2018

A new release of Alt-Ergo (version 2.2.0) is available.

You can get it from Alt-Ergo’s website. An OPAM package for it will be published in the next few days.

The major novelty of this release is a new experimental front-end that supports the SMT-LIB 2 language, extended prenex polymorphism. This extension is implemented as a standalone library, and is available here: https://github.com/Coquera/psmt2-frontend

The full list of CHANGES is available here. As usual, do not hesitate to report b…


Visiting the camels - MirageOS spring hack retreat 2018 — MirageOS (Stefanie Schirmer), Apr 20, 2018

Original posted on linse's blog.

Jemaa El Fnaa Image by Luc Viatour / https://Lucnix.be

In March 2018, I attended my first MirageOS hack retreat in Morrocco. MirageOS is a library operating system which allows everyone to build very small, specialized operating system kernels that are intended to run directly on the virtualization layer. The application code itself is the guest operating system kernel, and can be deployed at scale without the need for an extra containerization step in between. It is written …


The Bitcoin Piñata - no candy for you — Hannes Mehnert (hannes), Apr 18, 2018


On February 10th 2015 David Kaloper-Meršinjak and Hannes Mehnert launched (read also Amir's description) our bug bounty program in the form of our Bitcoin Piñata MirageOS unikernel. Thanks again to IPredator for both hosting our services and lending us the 10 Bitcoins! We analysed a bit more in depth after running it for five months. Mindy recently wrote about whacking the Bitcoin Piñata.

On March 18th 2018, after more than three years, IPredator, the lender of the Bitcoins,…


Whacking the Bitcoin Piñata — Mindy Preston, Apr 17, 2018

@yomimono or @hannesm surely know if people have tried crowbar on the BTC Piñata. – @kensan@mastodon.social

tl;dr - yes, and it seems that ocaml-x509 is not trivially easy to trick.


The Bitcoin Piñata

In 2015 David Kaloper-Mersinjak and Hannes Mehnert released ocaml-tls, an implementation of TLS (formerly known as SSL) written fully in OCaml. A full writeup of the stack is available in their Usenix Security 2015 paper, and as a series of blog posts on mirage.io. To acc…


Coq 8.8.0 is out — Coq, Apr 17, 2018

The final release of Coq 8.8.0 is available. It features better performances, tactic improvements, many enhancements for universe users, a new Export modifier for setting options, support for goal selectors in front of focusing brackets and a new experimental -mangle-names option for linting proof scripts. Feedback and bug reports are extremely welcome.

Taskforce on the Tezos Protocol, and Tzscan evolution — OCamlPro, Apr 13, 2018

As we are preparing to work on the Tezos Protocol, we’re still actively keeping the pace on the block explorer TZScan.io, adding cool information for baking accounts. We’d like to allow people to see who is contributing to the network and to understand the distribution of rolls, rights, etc.

For starters, we are showing the roll balance used for baking in the current cycle and the rolls history of a baker.


Enjoy, mo…


How to quantify quantifiers: an Ltac puzzle — GaGallium (Armaël Guéneau), Apr 05, 2018

In some occasions, using the Coq proof assistant stops resembling a normal software development activity, and becomes more similar to puzzle solving.

Similarly to the excellent video games of the Zachtronics studio (TIS-100, SpaceChem, …), the system provides you with puzzles where obstacles have to be side-stepped using a fair amount of tricks and ingenuity, and finally solving the problem has often no other utility than the satisfaction of having completed it.

In this blog-post, I would li…


OCaml JTRT — OCamlPro, Apr 01, 2018

This time of the year is, just like Christmas time, a time for laughs and magic… although the magic we are talking about, in the OCaml community, is not exactly nice, nor beautiful. Let’s say that we are somehow akin to many religions: we know magic does exist , but that it is satanic and shouldn’t be introduced to children.

Introducing Just The Right Time (JTRT)

Let me first introduce you to the concept of ‘Just The Right Time’ [1]. JTRT is somehow a ‘Just In…


Announcing the Sound Static Analysis for Security Workshop (2018-06-27 and 28 at NIST). See the whole programhere. — Frama-C, Mar 22, 2018

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