OCaml Weekly News

On behalf of the dune team, I'm pleased to announce the release of dune 1.11.0. This release contains quite a few new interesting features such as custom dialects: anyone can define their own OCaml based syntax. Is anyone up to revive the revised syntax? :slight_smile: I'd also like to highlight the the re-launch of variants feature in a sounder form, a new build-info library that queries build information, and that dune init can initialize an entire project. But of course, by far the most important thing is that the compiler's colours are now back :champagne:

The release of OCaml version 4.08.1 is almost here, we have created a second release candidate that you can test.

This new release candidate combines the rc1 fix for compilation failures in presence of "-pack" reported by Fabian @copy (breaking nocrypto), with a new fix for dynlinking failures in bytecode mode reported by Andre Maroneze (breaking Frama-C).

The source code is available at these addresses:

 https://github.com/ocaml/ocaml/archive/4.08.1+rc2.tar.gz
 https://caml.inria.fr/pub/distrib/ocaml-4.08/ocaml-4.08.1+rc2.tar.gz

The compiler can also be installed as an OPAM switch with one of the following commands:

opam switch create ocaml-variants.4.08.1+rc2 --repositories=default,ocaml-beta=git+https://github.com/ocaml/ocaml-beta-repository.git

or

opam switch create ocaml-variants.4.08.1+rc2+<VARIANT> --repositories=default,ocaml-beta=git+https://github.com/ocaml/ocaml-beta-repository.git

where you replace <VARIANT> with one of these:

• afl
• default-unsafe-string
• force-safe-string
• flambda
• fp
• fp+flambda

We want to know about all bugs. Please report them here: https://github.com/ocaml/ocaml/issues

Happy hacking, Florian Angeletti, for the OCaml team.

It's my pleasure to announce the first release of Down:

Down is an unintrusive user experience upgrade for the ocaml toplevel (REPL).

Simply load the zero dependency Down library in the ocaml toplevel and you get line edition, history, session support and identifier completion and documentation (courtesy of ocp-index).

Add this to your ~/.ocamlinit:

#use "down.top"

Down is distributed under the ISC license.

Down has no library dependency hence it should be easy to get installed and working in more constrained environments. In particular it works with ocamlnat.

Down is also toplevel environmentally friendly: it just adds the Down module to your scope and installs a SIGWINCH signal handler.

The Down manual can be consulted here and is available to you locally via odig doc down.

Homepage: https://erratique.ch/software/down
Installation: opam install down

We've added the OCaml client generator to the OpenAPI Generator project. To generate an OCaml client given an OpenAPI/Swagger specification file, please follow 3 simple steps below:

1. Download the Java JAR https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.1.0-SNAPSHOT/openapi-generator-cli-4.1.0-20190729.024538-72.jar
2. Rename the JAR as "openapi-generator-cli.jar"
3. Run the following command to generate an OCaml API client for the Petstore API:

Mac/Linux:

java -jar openapi-generator-cli.jar generate -g ocaml -i https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml -o /var/tmp/ocaml

Windows:

java -jar openapi-generator-cli.jar generate -g ocaml -i https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml -o C:\tmp\ocaml

If you've any feedback or question, please let us know by opening an issue in the Github repo.

Thanks Christophe Gensoul for contributing the new generator (https://github.com/OpenAPITools/openapi-generator/pull/3446).

findlib-1.8.1 is out:

• fixes an issue with upcoming ocaml-4.09 (-vmthreads gone)
• support for loading packages by prefix

For manual download, manuals, etc. see here:

http://projects.camlcity.org/projects/findlib.html

An updated OPAM package will follow soon.

Sorry for the delay.

I’m pleased to announce the first release of nice_parser, a single functor library that wraps your {menhir, ocamlyacc}-generated parser with a nice, high-level interface with beautiful loaction-aware error messages:

opam install nice_parser
ocaml
#use "topfind";;
#require “nice_parser”;;
#show_module Nice_parser.Make;;
module Make :
  functor (P : Nice_parser.RAW_PARSER) ->
    sig
      type token = P.token
      type result = P.result
      exception LexError of { msg : string; loc : Location.t; }
      exception ParseError of { token : token; loc : Location.t; }
      val pp_exceptions : unit -> unit
      val parse_string : ?pos:Lexing.position -> string -> result
      val parse_chan : ?pos:Lexing.position -> in_channel -> result
      val parse_file : string -> result
    end

The library relies on OCaml 4.08's new source highlighting mechanism for pretty lexing and parsing errors,

File "examples/illegal.katbb", line 1, characters 10-17:
1 | this!; is illegal!; isntit?
              ^^^^^^^
Error: [parser] unexpected token

but can also be used with earlier versions of OCaml.

The nice_parser repository includes an example that helps you get started with your own parser in seconds. The API is documented here.

Happy parsing!

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

• Down