Here is the latest OCaml Weekly News, for the week of April 24 to May 01, 2018.
Archive: https://discuss.ocaml.org/t/emacs-package-for-automatic-type-display/1897/2Continuing this thread, Louis Roché announced:
I recorded a short screencast to help understand what the tool is now doing: https://d.khady.info/merlin-auto-hl.ogv In the list of features that I would like to add, there is also the display of documentation. If the type is one line long and the documentation is short too, it might be possible to display it in a nice way.Louis Roché later added:
The repository has been updated. There is a proper readme. Including installation and usage sections. It can be installed using quelpa, so there is no need to clone the repository by hand. Also some bugs have been fixed. I think this is ready for usage now. And I will try to add features.
Archive: https://discuss.ocaml.org/t/ocaml-for-data-science/1878/14Continuing this thread, Akinori Abe said:
Hi. Sorry for late reply. I'm using OCaml for data science at work. > What makes OCaml good/bad for data science (long story short of your > experience with OCaml in this area)? - (Good) OCaml is fast. - (Good) Static typing prevents many small bugs. For example, Python often shows me errors like not found key in dict after long-time computation, but OCaml finds them in compile time (when we use records). - (Bad) OCaml Libraries for machine learning are less than Python. - (Bad) OCaml cannot support multicore. > What the OCaml alternatives for Python’s Pandas, NumPy, SciPy, etc.? As some people mentioned, owl is similar to numpy. > Do you know some frontier companies/products/projects that uses OCaml for data > science? I don't know. I use OCaml for data science personally. However, my colleagues use their favorite languages, e.g., Java, Python, etc. > Is there any problems that are related to data science and was solved by other > platforms, but not by OCaml as a platform? Lack of libraries, multi-core support and scalable distributed-memory processing environments (I know some opam packages such as rpc_parallel, but I cannot find enough examples). > Maybe you may give me a good piece advise related to both OCaml and data science. Jupyter (http://jupyter.org/) is very useful and it can execute OCaml code: https://akabe.github.io/ocaml-jupyter/. A Docker image containing many packages for data science is available: https://github.com/akabe/docker-ocaml-jupyter-datascience, and some examples are at https://github.com/akabe/docker-ocaml-jupyter-datascience/tree/master/notebooks. Please try them, if you are interested.UnixJunkie then replied:
"OCaml cannot support multicore". Sorry, but unless you are under windows, look for the following libraries in opam: parmap, parany, ocamlnet, etc. I run parallel OCaml programs everyday. Parmap is a good start. There are even more such libraries that I did not mention.UnixJunkie later added:
Some people (like this person https://github.com/examachine) are using the OCaml MPI bindings in production. If you really want to create salable distributed applications, I would advize using the zmq OCaml bindings available in opam (zmq, it would force you to program in an agent-based style, a la Erlang). I have done it once in the past, and it was pretty fun to write: https://github.com/UnixJunkie/daft
Archive: https://discuss.ocaml.org/t/what-is-a-good-and-maintained-sql-toolkit-for-ocaml/1915/2Michel Perez asked and Bobby Priambodo replied:
> I'd like to know about a good toolkit for sql handling in ocaml If you're talking about building queries only, there's Sequoia: https://github.com/andrenth/sequoia If you're talking about actually interfacing with an SQL database, there's Caqti: https://github.com/paurkedal/ocaml-caqti There are also several engine-specific libraries, such as postgresql-ocaml, pgocaml, pgx, ocaml-mysql, etc.Andre Nathan also replied:
There’s also sqlgg, which offers a code generation approach: https://github.com/ygrek/sqlgg
Archive: https://discuss.ocaml.org/t/patoline-an-advanced-typesetting-written-in-ocaml/1918/1Olivier Nicole announced:
Just recently, the Patoline project (http://patoline.org/) seems to have regained activity. Since I'm very interested in it I'm writing this post so that others may learn about its existence. From my experience of writing a mid-sized document (internship report) with Patoline, the tool is very nice to use (especially for OCaml programmers) and very promising! However, it suffers from a few shortcomings typical of free software projects: lack of advanced documentation, and obligation for the user to learn about the software's internals when they want to customize their rendering in unusual ways. I hope to find some time to contribute to Patoline this year!
Archive: https://sympa.inria.fr/sympa/arc/caml-list/2018-04/msg00094.htmlEnrico Tassi announced:
We are proud to announce the immediate availability of ELPI 1.0. ELPI stands for Embeddable λProlog Interpreter, and is implemented in OCaml. ELPI implements a variant of λProlog enriched with Constraint Handling Rules, a programming language well suited to manipulate syntax trees with binders. ELPI is designed to be embedded into larger applications written in OCaml as an extension language. It comes with an API to drive the interpreter and with an FFI for defining built-in predicates and data types, as well as quotations and similar goodies that come in handy to adapt the language to the host application. The ELPI programming language has the following features: - Native support for variable binding and substitution, via an Higher Order Abstract Syntax (HOAS) embedding of the object language. The programmer needs not to care about De Bruijn indexes. - Native support for hypothetical context. When moving under a binder one can attach to the bound variable extra information that is collected when the variable gets out of scope. For example when writing a type-checker the programmer needs not to care about managing the typing context. - Native support for higher order unification variables, again via HOAS. Unification variables of the meta-language (λProlog) can be reused to represent the unification variables of the object language. The programmer does not need to care about the unification-variable assignment map and cannot assign to a unification variable a term containing variables out of scope, or build a circular assignment. - Native support for syntactic constraints and their meta-level handling rules. The generative semantics of Prolog can be disabled by turning a goal into a syntactic constraint (suspended goal). A syntactic constraint is resumed as soon as relevant variables gets assigned. Syntactic constraints can be manipulated by constraint handling rules (CHR). - Native support for backtracking. To ease implementation of search. - The constraint store is extensible. The host application can declare non-syntactic constraints and use custom constraint solvers to check their consistency. - Clauses are graftable. The user is free to extend an existing program by inserting/removing clauses, both at runtime (using implication) and at "compilation" time by accumulating files. ELPI is free software released under the terms of LGPL 2.1 or above. See https://github.com/LPCIC/elpi for installation instructions.
Archive: https://sympa.inria.fr/sympa/arc/caml-list/2018-04/msg00097.htmlJocelyn Sérot announced:
This is just to announce that the OPAM package (including the library and the CL compiler) is now available at https://opam.ocaml.org/packages/rfsm Thanks for the OPAM maintainer(s) for the help during the publication process.
Here are links from many OCaml blogs aggregated at OCaml Planet, http://ocaml.org/community/planet/. Full Time: Software Developer (Functional Programming) at Jane Street in New York, NY; London, UK; Hong Kong http://jobs.github.com/positions/0a9333c4-71da-11e0-9ac7-692793c00b45 Full Time: Compiler Engineer at Jane Street in New York & London http://jobs.github.com/positions/9e8ba450-e72e-11e7-926f-6ce07b7015c8
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