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

Alan Schmitt
2020-01-21T14:08:46Z

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Hello

Here is the latest OCaml Weekly News, for the week of January 14 to 21,
2020.

Table of Contents
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How does the compiler check for exhaustive pattern matching?
resto 0.2 released
opam 2.0.6 release
soupault: a static website generator based on HTML rewriting
Spin: Project scaffolding tool and set of templates for Reason and OCaml
Old CWN

How does the compiler check for exhaustive pattern matching?
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Archive:
<https://discuss.ocaml.org/t/how-does-the-compiler-check-for-exhaustive-pattern-matching/5013/1>

Dylan Irlbeck asked
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Hi all. I'm relatively new to OCaml, and I was curious on how the
compiler is able to give a warning when a case list is non-exhaustive
- both from a high-level and, if possible, the implementation of this
check. I have some ideas about how one could do this, but none of my
ideas seem like they'd be nearly as efficient as the OCaml compiler
is.

gasche replied
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The canonical reference for exhaustivity-checking in OCaml is the
scientific publication

[Warnings for pattern matching] Luc Maranget 2007

The general idea is to consider all the patterns of a given
pattern-matching at once, generalize this structure to a "matrix" of
patterns (matching on several values in parallel), and devise an
algorithm to "explore" these pattern matrices in such a way that you
eventually tell if a given pattern-matrix is exhaustive, or can
propose a counter-example.

(I guess we should write a high-level/accessible blog post about
this.)

[Warnings for pattern matching]
<http://moscova.inria.fr/~maranget/papers/warn/index.html>

resto 0.2 released
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Archive: <https://discuss.ocaml.org/t/ann-resto-0-2-released/5028/1>

Raphaël Proust announced
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On behalf on Nomadic Labs, I'm happy to announce the release of
version 0.2 of `resto', a library to create type-safe HTTP/JSON
services.

The library is available through opam (`opam install resto'),
distributed under LGPL, and hosted on
<https://gitlab.com/nomadic-labs/resto>.

`resto' was previously released as `ocplib-resto' maintained by
OCamlPro. The project is now maintained by Nomadic Labs.

Along with many bugfixes and a few added features, the main change of
this release is that the library is split into multiple packages with
fine-grained dependencies.

opam 2.0.6 release
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Archive: <https://discuss.ocaml.org/t/ann-opam-2-0-6-release/5038/1>

R. Boujbel announced
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We are pleased to announce the minor release of [opam 2.0.6].

This new version contains mainly build update & fixes. You can find
more information in this [blog post].

_opam is a source-based package manager for OCaml. It supports
multiple simultaneous compiler installations, flexible package
constraints, and a Git-friendly development workflow._

[opam 2.0.6] <https://github.com/ocaml/opam/releases/tag/2.0.6>

[blog post] <https://opam.ocaml.org/blog/opam-2-0-6>

soupault: a static website generator based on HTML rewriting
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Archive:
<https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/11>

Daniil Baturin announced
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soupault 1.8.0 is [released] along with Lua-ML 0.9.1.

Lua-ML now raises `Failure' when Lua code execution fails. There's
much room for improvement in that area, for now I've just done
something that is better than just displaying errors on stderr but
otherwise allowing syntax and runtime errors pass silently.

If you have any ideas how perfect interpreter error reporting _should_
work, please share!

As of improvements in soupault itself, there's now:
• A way for plugins to specify their minimum supported soupault
version like `Plugin.require_version("1.8.0")'
• `TARGET_DIR' environment variable and `target_dir' Lua global that
contains the directory where the rendered page will be written, to
make it easier for plugins/scripts to place processed assets
together with pages.
• "Build profiles": if you add `profile = "production"' or similar to
widget config, that widget will be ignored unless you run `soupault
--profile production'.
• A bunch of new utility functions for plugins.

[released] <https://soupault.neocities.org/blog/soupault-1.8.0-release/>

Spin: Project scaffolding tool and set of templates for Reason and OCaml
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Archive:
<https://discuss.ocaml.org/t/spin-project-scaffolding-tool-and-set-of-templates-for-reason-and-ocaml/5047/1>

Mohamed Elsharnouby announced
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<https://github.com/tmattio/spin>

Old CWN
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[Alan Schmitt]

[send me a message] <mailto:alan.schmitt@polytechnique.org>

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

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

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