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Here is the latest OCaml Weekly News, for the week of December 04 to 11, 2018.

Table of Contents

ppx_yojson 0.2.0

Nathan Rebours announced

I'm happy to announce I just released version 0.2.0 of ppx_yojson.

ppx_yojson is a ppx rewriter that helps you work with Yojson by allowing you to write concise and expressive json expressions and patterns.

Version 0.2.0 comes with a set of new features which makes it much more usable and less proof-of-concepty. This includes a new extension to write Yojson patterns and anti-quotation for the expressions extension. Hopefully it will attract more users.

Full release notes are available here.

ppx_yojson can be found on github and opam.

Let me know if you have some feedback or if it lacks anything for you to be able to use it!

New release of fix

François Pottier announced

I would like to announce a new release of fix, an OCaml library that provides facilities for memoization, hash-consing, and least-fixed-point computations.

The library can be installed as follows:

opam update && opam install fix.20181130

The repository's README offers some documentation and links to demos:


In particular, this demo, a conversion of regular expressions to finite-state automata by Brzozowski's method, illustrates many of the facilities offered by the library:


François Pottier later added

All right, it should work now – sorry for the noise:

opam update && opam install fix.20181206

Thanks to Tuncer Ayaz for reporting the problem and to Kate for helping me fix it.

Interesting OCaml Articles

Yotam Barnoy announced

Presentation on Mirage OS by our own @dinosaure!

bs-platform 4.0.8 is released

Hongbo Zhang announced

LablGtk3 beta1

Jacques Garrigue announced

Due to the planned deprecation of gtksourceview2 in Debian, we have been working on a stripped down port of LablGtk2 to Gtk-3.

A first beta is available for download at the usual location:

There is no opam package yet, because I’m not sure how to do that: I seem to need to add a new conf-gtksourceview3 package too, and I’m not sure how to proceed. Help accepted.

Note that this is not the originally planned introspection based port, but a manual port of lablgtk2, dropping widgets that are no longer available. It is of course possible to add new widgets if people are willing to contribute.

The main goal is to allow application using lablgtksourceview, such as CoqIDE, to compile on top of Gtk-3. Since Gtk-2 itself stays available, lablgtk2 will continue to be supported for other applications.

The code is in the lablgtk3 branch:
There is an ongoing discussion

The current status is that a modified version of CoqIDE compiles and runs.

Please report issues on GitHub.

Other OCaml News

From the ocamlcore planet blog

Here are links from many OCaml blogs aggregated at OCaml Planet.


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