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

Alan Schmitt
2020-05-05T07:45:47Z

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Hello

Here is the latest OCaml Weekly News, for the week of April 28 to May
05, 2020.

Table of Contents
─────────────────

Lwt now has let* syntax
JOSE 0.3.0 - Now with 100% more encryption
Are there learning materials for OCaml for those with no programming experience?
The recent evolution of utop, lambda-term, zed and underneath projects
Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
Old CWN

Lwt now has let* syntax
═══════════════════════

Archive: [https://discuss.ocaml.org/t/lwt-now-has-let-syntax/5651/1]

Anton Bachin announced
──────────────────────

[Lwt] now has `let*' and `let+' syntax, which can be used like this:

┌────
│ open Lwt.Syntax
│
│ let () =
│ let request =
│ let* addresses = Lwt_unix.getaddrinfo "google.com" "80" [] in
│ let google = Lwt_unix.((List.hd addresses).ai_addr) in
│
│ Lwt_io.(with_connection google (fun (incoming, outgoing) ->
│ let* () = write outgoing "GET / HTTP/1.1\r\n" in
│ let* () = write outgoing "Connection: close\r\n\r\n" in
│ let* response = read incoming in
│ Lwt.return (Some response)))
│ in
│
│ let timeout =
│ let* () = Lwt_unix.sleep 5. in
│ Lwt.return None
│ in
│
│ match Lwt_main.run (Lwt.pick [request; timeout]) with
│ | Some response -> print_string response
│ | None -> prerr_endline "Request timed out"; exit 1
└────

This is now released in Lwt [5.3.0]. Thanks to Rahul Kumar for adding
`let*', and @CraigFe for adding `let+'!

[Lwt] https://github.com/ocsigen/lwt

[5.3.0] https://github.com/ocsigen/lwt/releases/tag/5.3.0

Thomas Coopman asked
────────────────────

Awesome this looks great.

2 quick questions:

1. I don't see this new version documented on ocsigen yet? Is that a
build that needs to be done manually?
2. Is `ppx_lwt' still recommend for some usecases like `try%'? For
what cases is one preferred over the other?

Anton Bachin replied
────────────────────

Good questions :slight_smile:

1. The docs generation is blocked on an Ocsigen "internal" package
`wikidoc', which has not been updated to support 4.08. So,
effectively, `let*' is exactly what is preventing docs generation
for the time being. I'll post the docs as soon as that is fixed.
2. `ppx_lwt' is probably still the recommended way, because of better
backtraces, and things like `try%lwt'. `let*' is nice for people
that don't want to use the PPX. They can still benefit from a
monadic syntax.

JOSE 0.3.0 - Now with 100% more encryption
══════════════════════════════════════════

Archive:
[https://discuss.ocaml.org/t/ann-jose-0-3-0-now-with-100-more-encryption/5667/1]

Ulrik Strid announced
─────────────────────

I recently released a version 0.3.0 of JOSE.

[https://github.com/ulrikstrid/reason-jose]
[https://ulrikstrid.github.io/reason-jose]

It now includes some of the JWE (JSON Web Encryption) spec. A huge
thank you goes out to @hannes for helping me implementing one of the
gnarlier combinations of decryption that I could then use as a base
for encryption and more `alg' and `enc'.

I also refactored the JWK (JSON Web Keys) implementation to unify and
simplify the representation. It is now possible to use a private key
for anything a public key can do since it's a superset.

A special thanks to @anmonteiro for helping me with the design and
reviewing my code.

Are there learning materials for OCaml for those with no programming experience?
════════════════════════════════════════════════════════════════════════════════

Archive:
[https://discuss.ocaml.org/t/are-there-learning-materials-for-ocaml-for-those-with-no-programming-experience/5684/1]

Aaron Christianson asked
────────────────────────

OCaml is a language with some advanced features, but a very gentle
learning curve. It seems like it would be well-suited to teaching
beginners to program (a few tricky error messages notwithstanding),
but I haven't seen many resources targeted at teaching programming
from scratch. Does anyone here know any?

Daniel Bünzli replied
─────────────────────

There is [*OCaml from the Very Beginning*] written by @JohnWhitington.

[*OCaml from the Very Beginning*] http://ocaml-book.com/

Nicolás Ojeda Bär also replied
──────────────────────────────

An excellent (free) book is "LE LANGAGE CAML"
[https://caml.inria.fr/pub/distrib/books/llc.pdf].

Pierre also replied
───────────────────

There's also [CS3110] from Cornell University. Here's [the
textbook]. It's pretty great!

[CS3110] https://www.cs.cornell.edu/courses/cs3110/2020sp/

[the textbook]
https://www.cs.cornell.edu/courses/cs3110/2019sp/textbook/

The recent evolution of utop, lambda-term, zed and underneath projects
══════════════════════════════════════════════════════════════════════

Archive:
[https://discuss.ocaml.org/t/the-recent-evolution-of-utop-lambda-term-zed-and-underneath-projects/5687/1]

ZAN DoYe announced
──────────────────

Hi, dear OCaml guys! We've been keeping quiet for more than one year
though utop, lambda-term, zed and some related projects were still
evolving during the period of time. This is because of two reasons:

1. The new feature had nothing to do with the fields where most OCaml
developers are working on:

[https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/a30d5fb6fc075a50801b387299cc820965d48ca0.png]

[https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/9/91b88f0c492702212f00f17af1bf0e18ee1a463b.png]

Recognizing, editing, fuzzy searching for Character
Variation(mainly for ancient CJK characters).

Nevertheless, the new feature brought us a good side effect – the
long-existing [Issue with asian charset] was resolved. UTop users
will notice the refinement naturally, so no announcement was
needed.

2. I didn't deem the first few new editions of zed 2 and lambda-term 2
stable enough.

[Issue with asian charset]
https://github.com/ocaml-community/lambda-term/issues/2

3.0 era
╌╌╌╌╌╌╌

This time, we are entering zed 3, lambda-term 3 era. The features
introduced since zed 2, lambda-term 2 are quite stable now and the new
feature coming to us will have a bit more impact, especially to vim
users. So it's worthwhile to draft an announcement:

◊ VI Editing Mode

[https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/c/ca11924046977d89d4345ad135977c6960470edc.gif]

OCaml guys, hope you enjoy this.

List of notable changes:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

• zed 2:
• wide, combined glyph(Character Variation, IPA, CJK …)
• add wanted_column support for wide width character

• lambda-term 2:
• wide, combined glyph(Character Variation, IPA, CJK …)
• add horizontal scrolling support for wide width character

• zed 3:
• add new actions for convenience

• lambda-term 3:
• `LTerm_read_line': add initial support for vi editing mode:
• motions:
• h l 0 ^ $
• j k gg G
• w W e E b B ge gE
• f F t T
• aw iw aW iW
• include or inner ( ), [ ], { }, < >, ' and "
• generic quote: aq? iq? where ? could be any character
• bracket matching: jump back and forth between matched brackets
• delete, change, yank with motions
• paste: p P
• line joining: J

for a full list of the changes, please visit the homepages of each
project.

Projects underneath:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

• [charInfo_width]: Determine column width for a character
• [mew] & [mew_vi]: Modal editing witch & Its VI interpreter
complement. In a word, modal editing engine generators.

[charInfo_width] https://bitbucket.org/zandoye/charinfo_width/

[mew] https://github.com/kandu/mew

[mew_vi] https://github.com/kandu/mew_vi

What's next
╌╌╌╌╌╌╌╌╌╌╌

◊ VI Editing Mode

1. Visual mode

[https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/7/7cc45010710ad28d8d1e859e9b28806469ef8080.gif]
2. register support and more vi compatible

◊ CJKV

We've recorded more then 100 thousand entries about the structure of
CJK characters, what is a character consists of, how are the
sub-assemblies glue together etc. And as a complement to
charInfo_width, we may release a new project called charInfo_structure
;)

Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
═══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════

Archive:
[https://discuss.ocaml.org/t/looking-for-lovely-idiomatic-examples-of-ocaml-used-for-shell-scripting-in-the-manner-of-perl-python-but-esp-perl/5703/1]

Chet Murthy announced
─────────────────────

I wonder if there are people who have written nontrivial Ocaml code
for shell-scripting, that they think exemplifies the right way to do
it. I've been a Perl hacker for 25yr, and so when I reach for Ocaml
to write stuff that should be Perl shell-scripts, I always find it a
bit painful, and there's a significant overhead to getting the job
done. Some of that is applying ocaml to a new domain, but some of it
is that I'm just not using the right idioms and tools (and there are
so many to choose from).

So if anybody has good pointers, I'd appreciate learning about them.

Bikal Lem
─────────

Haven't tried it myself, but this looks promising …
[https://github.com/janestreet/shexp].

At least it has the great Sean Connery in its README so possibly worth
delving a bit. :)

Hezekiah Carty
──────────────

[bos] seems like it can do a lot of what you're looking for. It's at
least worth taking a look, though it may not be at Perl levels of
concise for this kind of task.

[bos] https://erratique.ch/software/bos

Martin Jambon
─────────────

I tried to summarize my take on the subject into this gist:
[https://gist.github.com/mjambon/bb07b24f89fa60c973735307ce9c6cb9]

I'm not aware of the existence of such tool, but this is how I might
design it. This should be reminiscent of camlp4's quotation and
anti-quotation system, which allows alternating between two syntaxes
within a source file.

Old CWN
═══════

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[Alan Schmitt]

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

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