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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.

1028 blog posts are available. You can read the 30 more recent ones below or view older ones.

Fixin' your automata — GaGallium (François Pottier), Dec 05, 2018

There are several ways of compiling a regular expression (RE) down to a deterministic finite-state automaton (DFA). One such way is based on Brzozowski derivatives of regular expressions. In this post, I describe a concise OCaml implementation of this transformation. This is an opportunity to illustrate the use of fix, a library that offers facilities for constructing (recursive) memoized functions and for performing least fixed point computations.

From REs to DFAs, via Brzozowski derivati…

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Site Reliability Engineer (SRE II) — GitHub Jobs, Dec 03, 2018

Description - Site Reliability Engineer (SRE II) Company Overview: As a member of the corporate team, you’ll focus on enhancing the relationship with our clients as we provide outstanding business solution services. Within departments like Accounting & Finance, Human Resources, and Engineering, Conduent is actively staffing all teams with roles like Recovery Analyst, Client Services Specialist, and Senior Management Consultant. At Conduent, we give our employees the opportunity to further dev…Read more...

Software Engineer II (Programming Languages) — GitHub Jobs, Dec 03, 2018

Description – Software Engineer II (Programming Languages) Company Overview: As a member of the corporate team, you’ll focus on enhancing the relationship with our clients as we provide outstanding business solution services. Within departments like Accounting & Finance, Human Resources, and Engineering, Conduent is actively staffing all teams with roles like Recovery Analyst, Client Services Specialist, and Senior Management Consultant. At Conduent, we give our employees the opportunity t…Read more...

Software Engineer (Front-End Engineer II) — GitHub Jobs, Dec 03, 2018

Description – Software Engineer (Front-End Engineer II) Company Overview: As a member of the corporate team, you’ll focus on enhancing the relationship with our clients as we provide outstanding business solution services. Within departments like Accounting & Finance, Human Resources, and Engineering, Conduent is actively staffing all teams with roles like Recovery Analyst, Client Services Specialist, and Senior Management Consultant. At Conduent, we give our employees the opportunity to fu…Read more...

Frama-C 18.0 (Argon) is out. Download ithere. — Frama-C, Nov 29, 2018

Senior Haskell / Full Stack Developer at PRODA Ltd (Full-time) — Functional Jobs (FunctionalJobs.com), Nov 26, 2018

Position summary

We are looking for senior Haskell engineers to join our team in London or work remotely.

We want you to be someone who is looking to really help shape the future of the development team, have real impact on strategy, architecture and be the lead on our most important projects.

You will expand our application’s capabilities in data ingestion, data exports, data standardisation and machine learning. We work in a functional programming stack in Haskell and Elm, together wi…

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Safely typing algebraic effects — GaGallium (Nathanaël Courant), Nov 26, 2018

Last year (2017), I was following the MPRI, a research-oriented master programme in Paris. The project for the Functional programming and type systems course (taught by François Pottier, Didier Rémy, Yann Régis-Gianas and Pierre-Évariste Dagand) was to write a compiler for a tiny functional language. I extended that project with algebraic effects and a static type system checking that effects could not be unhandled. Explaining the type system of my implementation is what this post is about…

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Front End Developer (ReactJS & Purescript) — GitHub Jobs, Nov 23, 2018

## Context The Complex Systems Institute of Paris (ISC-PIF) is a place dedicated to the development of innovative and interdisciplinary research on complex systems at the crossroad between modeling, high performance computing and Big Data. ISC-PIF is a unit of the National Center for Scientific Research (UPS3611), the largest and most prestigious french research organizations. ISC-PIF is developing new methods and tools to explore and interact with science at the level of a research communitie…Read more...

An Introduction to Tezos RPCs: Signing Operations — OCamlPro, Nov 21, 2018

In a previous blog post, we presented the RPCs used by tezos-client to
send a transfer operation to a tezos-node. We were left with two
remaining questions:

* How to forge a binary operation, for signature
* How to sign a binary operation

In this post, we will reply to these questions. We are still assuming
a node running and waiting for RPCs on address 127.0.0.1:9731. Since we will ask this node to forge a request, we really need to trust it, as a malicious node could send a different binary tr…

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An Introduction to Tezos RPCs: a Basic Wallet — OCamlPro, Nov 15, 2018

In this technical blog post, we will briefly introduce Tezos RPCs through a simple example: we will show how the tezos-client program interacts with the tezos-node during a transfer command. Tezos RPCs are HTTP queries (GET or POST) to which tezos-node replies in JSON format. They are the only way for wallets to interact with the node. However, given the large number of RPCs accepted by the node, it is not always easy to understand which ones can be useful if you want to write a wallet. So, here…

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Parser Construction With Menhir: A Couple Appetizers — GaGallium (François Pottier), Nov 14, 2018

This post is a shameless advertisement for Menhir, a parser generator for OCaml. It illustrates Menhir’s new input syntax, which was introduced on November 13, 2018. The code fragments shown below are excerpts of valid .mly files.

Ingredients

Suppose I would like to parse and evaluate our good old friends, the arithmetic expressions. For instance, the string "(3 + 4) * 5 - 9" should be accepted and evaluated to the value 26.

I assume that I have a lexical analyzer that can chop…

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First Open-Source Release of TzScan — OCamlPro, Nov 08, 2018

In October 2017, after the Tezos ICO, OCamlPro started to work on a block explorer for Tezos. For us, it was the most important software that we could contribute to the community, after the node itself, of course. We used it internally to monitor the Tezos alphanet, until its official public release in February 2018, as TzScan. One of TzScan main goals was to make the complex DPOS consensus algorithm of Tezos easier to understand, to follow, especially for bakers who will contribute to it.  Sin…

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Liquidity Tutorial: A Game with an Oracle for Random Numbers — OCamlPro, Nov 06, 2018

A Game with an oracle

In this small tutorial, we will see how to write a chance game on the Tezos blockchain with Liquidity and a small external oracle which provides random numbers.

Principle of the game

Rules of the game are handled by a smart contract on the Tezos blockchain.

When a player decides to start a game, she must start by making a transaction (i.e. a call) to the game smart contract with a number parameter (let’s call it n) between 0 and 100 (inclusively). The amount that is s…

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forge.ocamlcore.org expected downtime on 2018-11-01 — OCamlCore Forge News (Sylvain Le Gall), Nov 01, 2018

The forge and related websites will be down for a few hours on 2018-11-01 starting at around 20:30 CEST. The previous downtime was not enough to do the full migration [1]. I will do my best to keep the downtime as short as possible. In the meantime, you can use the "static" website that has been put in place: https://forge-static.ocamlcore.org [1]: https://forge.ocamlcore.org/forum/forum.php?forum_id=963

forge.ocamlcore.org expected downtime on 2018-10-30 — OCamlCore Forge News (Sylvain Le Gall), Nov 01, 2018

The forge and related websites will be down for a few hours on 2018-10-30 starting at around 21:00 CEST. I will do my best to keep the downtime as short as possible. In the meantime, you can use the "static" website that has been put in place: https://forge-static.ocamlcore.org

Compiler Engineer — GitHub Jobs, Nov 01, 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 …Read more...

Software Developer (Functional Programming) — GitHub Jobs, Nov 01, 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…Read more...

opam 2.0.1 is out! — OCaml Platform (Raja Boujbel - OCamlPro, Louis Gesbert - OCamlPro), Oct 24, 2018

We are pleased to announce the release of opam 2.0.1.

This new version contains mainly backported fixes, some platform-specific:

  • Cold boot for MacOS/CentOS/Alpine
  • Install checksum validation on MacOS
  • Archive extraction for OpenBSD now defaults to using gtar
  • Fix compilation of mccs on MacOS and Nix platforms
  • Do not use GNU-sed specific features in the release Makefile, to fix build on OpenBSD/FreeBSD
  • Cleaning to enable reproducible builds
  • Update configure scripts

And some opam specific:

  • git: fix git…
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ocaml-git 2.0 — Tarides (Romain C.), Oct 19, 2018

I'm very happy to announce a new major release of ocaml-git (2.0). This release is a 2-year effort to get a revamped streaming API offering a full control over memory allocation. This new version also adds production-ready implementations of the wire protocol: git push and git pull now work very reliably using the raw Git and smart HTTP protocol (SSH support will come soon). git gc is also implemented, and all of the basic bricks are now available to create Git servers. MirageOS support is a…

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OCamlPro’s TZScan grant proposal accepted by the Tezos Foundation – joint press release — OCamlPro, Oct 17, 2018

Tezos Foundation and OCamlPro joint press release – October 17, 2018

We are pleased to announce  that the Tezos Foundation has issued a grant to OCamlPro to support its work on TzScan, a block explorer for the Tezos blockchain that will be made open-source.

OCamlPro is a French company and R&D lab, focused on OCaml and blockchain development. OCamlPro, which is an active community member and contributor to Tezos, has initiated several Tezos-related projects such as TzScan and Liquidit…

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OCamlFormat 0.8 — Tarides (Guillaume P.), Oct 17, 2018

We are proud to announce the release of OCamlFormat 0.8 (available on opam). To ease the transition from the previous 0.7 release here are some highlights of the new features of this release. The full changelog is available on the project repository.

Precedence of options

In the previous version you could override command line options with .ocamlformat files configuration. 0.8 fixed this so that the OCamlFormat configuration is first established by reading .ocamlformat and .ocp-indent files:

ma…
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OCaml Workshop 2018 — Tarides (Romain C.), Sep 27, 2018

The OCaml Users and Developers Workshop brings together industrial users of OCaml with academics and hackers who are working on extending the language, type system and tools. OCaml 2018 was held on September 27th, 2018 in St. Louis, Missouri, USA, colocated with ICFP 2018.

Check Tarides' talks: RFCs, all the way down! and The OCaml Platform 1.0.

Coq 8.8.2 is out — Coq, Sep 26, 2018

The 8.8.2 release of Coq is available.

Main changes:

  • The kernel does not tolerate capture of global universes by polymorphic universe binders, fixing a soundness break (triggered only through custom plugins)
  • A PDF version of the reference manual is available once again.
  • The coq-makefile targets print-pretty-timed, print-pretty-timed-diff, and print-pretty-single-time-diff now correctly label the "before" and "after" columns, rather than swapping them.
  • The Windows installer now includes many mo…
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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…

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opam 2.0.0 release and repository upgrade — OCaml Platform (Raja Boujbel - OCamlPro, Louis Gesbert - OCamlPro), Sep 18, 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 fu…

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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…

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Dune 1.2.0 — Tarides (Etienne M.), Sep 06, 2018

After a tiny but important patch release as 1.1.1, the dune team is thrilled to announce the release of dune 1.2.0! Here are some highlights of the new features in that version. The full list of changes can be found in the dune repository.

Watch mode

When developing, it is common to edit a file, run a build, read the error message, and fix the error. Since this is a very tight loop and developers are doing this hundreds or thousands times a day, it is crucial to have the quickest feedback possi…

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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.

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!

Last stretch! Repository upgrade and opam 2.0.0 roadmap — OCaml Platform (Raja Boujbel - OCamlPro, Louis Gesbert - OCamlPro), Aug 02, 2018

A few days ago, we released opam 2.0.0~rc4, and explained that this final release candidate was expected be promoted to 2.0.0, in sync with an upgrade to the opam package repository. So here are the details about this!

If you are an opam user, and don't maintain opam packages

  • You are encouraged to upgrade) as soon as comfortable, and get used to the changes and new features

  • All packages installing in opam 1.2.2 should exist and install fine on 2.0.0~rc4 (if you find one that doesn't, please r…

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