[cwn] Attn: Development Editor, Latest OCaml Weekly News
Alan Schmitt
alan.schmitt at polytechnique.org
Mon Sep 16 23:42:33 PDT 2019
Hello
Here is the latest OCaml Weekly News, for the week of September 10
to
17, 2019.
Table of Contents
─────────────────
OCaml 4.09.0+beta2
chartjs: OCaml bindings for Chart.js charting library
How does one print any type?
Interesting OCaml Articles
Dune 2.0.0 coming soon!
Old CWN
OCaml 4.09.0+beta2
══════════════════
Archive:
<https://sympa.inria.fr/sympa/arc/caml-list/2019-09/msg00010.html>
Florian Angeletti announced
───────────────────────────
The release of OCaml 4.09.0 is approaching. We have created a
second
beta version to help you adapt your softwares to the new
features
ahead of the release.
This new beta integrates in particular the fixes from 4.08.1
that were
not yet part of the first beta due to the overlap between the
release
of 4.08.1 and the first beta.
If you tried to test the first beta, and were stopped by the
lack of
working dune and ocamlfind, those issues has been fixed.
The source code is available at these addresses:
• <https://github.com/ocaml/ocaml/archive/4.09.0+beta2.tar.gz>
•
<https://caml.inria.fr/pub/distrib/ocaml-4.09/ocaml-4.09.0+beta2.tar.gz>
The compiler can also be installed as an OPAM switch with one of
the
following commands.
┌────
│ opam switch create ocaml-variants.4.09.0+beta2
--repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
└────
or
┌────
│ opam switch create ocaml-variants.4.09.0+beta2+<VARIANT>
--repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
└────
where you replace <VARIANT> with one of these:
• afl
• default-unsafe-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 "octachron" Angeletti, for the OCaml team
OCaml 4.09.0
╌╌╌╌╌╌╌╌╌╌╌╌
(Changes that can break existing programs are marked with a "*")
◊ Code generation and optimizations:
• #2278: Remove native code generation support for 32-bit Intel
macOS,
iOS and other Darwin targets. (Mark Shinwell, review by
Nicolas
Ojeda Bar and Xavier Leroy)
• #8507: Shorten symbol names of anonymous functions in Flambda
mode
(the directory portions are now hidden) (Mark Shinwell, review
by
Nicolás Ojeda Bär)
• #7931, #1904: Add FreeBSD/aarch64 support (Greg V, review by
Sébastien Hinderer, Stephen Dolan, Damien Doligez and Xavier
Leroy)
• #8547: Optimize matches that are an affine function of the
input.
(Stefan Muenzel, review by Alain Frisch, Gabriel Scherer)
• #8681, #8699, #8712: Fix code generation with nested let rec
of
functions. (Stephen Dolan, Leo White, Gabriel Scherer and
Pierre
Chambart, review by Gabriel Scherer, reports by Alexey
Solovyev and
Jonathan French)
◊ Compiler user-interface and warnings:
• * #2276: Remove support for compiler plugins and hooks (also
adds
[Dynlink.unsafe_get_global_value]) (Mark Shinwell, Xavier
Clerc,
review by Nicolás Ojeda Bär, Florian Angeletti, David Allsopp
and
Xavier Leroy)
• #2301: Hint on type error on int literal (Jules Aguillon,
review by
Nicolás Ojeda Bär , Florian Angeletti, Gabriel Scherer and
Armaël
Guéneau)
• #2309: New options -with-runtime and -without-runtime in
ocamlopt/ocamlc that control the inclusion of the runtime
system in
the generated program. (Lucas Pluvinage, review by Daniel
Bünzli,
Damien Doligez, David Allsopp and Florian Angeletti)
• #2314: Remove support for gprof profiling. (Mark Shinwell,
review
by Xavier Clerc and Stephen Dolan)
• #3819, #8546 more explanations and tests for illegal
permutation
(Florian Angeletti, review by Gabriel Scherer)
• #8537: fix the -runtime-variant option for bytecode (Damien
Doligez,
review by David Allsopp)
• #8541: Correctly print multi-lines locations (Louis Roché,
review by
Gabriel Scherer)
• #8579: Better error message for private constructors of an
extensible variant type (Guillaume Bury, review by many fine
eyes)
◊ Compiler distribution build system:
• #2267: merge generation of header programs, also fixing
parallel
build on Cygwin. (David Allsopp, review by Sébastien
Hinderer)
• #8514: Use boot/ocamlc.opt for building, if available.
(Stephen
Dolan, review by Gabriel Scherer)
◊ Internal/compiler-libs changes:
• #1579: Add a separate types for clambda primitives (Pierre
Chambart,
review by Vincent Laviron and Mark Shinwell)
• #1965: remove loop constructors in Cmm and Mach (Vincent
Laviron)
• #1973: fix compilation of catches with multiple handlers
(Vincent
Laviron)
• #2190: fix pretty printing (using Pprintast) of "lazy …"
patterns
and "fun (type t) -> …" expressions. (Nicolás Ojeda Bär,
review by
Gabriel Scherer)
• #2228, #8545: refactoring the handling of .cmi files by moving
the
logic from Env to a new module Persistent_env (Gabriel
Scherer,
review by Jérémie Dimino and Thomas Refis)
• #2229: Env: remove prefix_idents cache (Thomas Refis, review
by
Frédéric Bour and Gabriel Scherer)
• #2237, #8582: Reorder linearisation of Trywith to avoid a call
instruction (Vincent Laviron and Greta Yorsh, additional
review by
Mark Shinwell; fix in #8582 by Mark Shinwell, Xavier Leroy and
Anil
Madhavapeddy)
• #2265: Add bytecomp/opcodes.mli (Mark Shinwell, review by
Nicolas
Ojeda Bar)
• #2268: Improve packing mechanism used for building
compilerlibs
modules into the Dynlink libraries (Mark Shinwell, Stephen
Dolan,
review by David Allsopp)
• #2277: Use newtype names as type variable names (Matthew Ryan)
• #2280: Don't make more Clambda constants after starting Cmmgen
(Mark
Shinwell, review by Vincent Laviron)
• #2281: Move some middle-end files around (Mark Shinwell)
• #2283: Add [is_prefix] and
[find_and_chop_longest_common_prefix] to
[Misc.Stdlib.List] (Mark Shinwell, review by Alain Frisch and
Stephen Dolan)
• #2284: Add various utility functions to [Misc] and remove
functions
from [Misc.Stdlib.Option] that are now in [Stdlib.Option]
(Mark
Shinwell, review by Thomas Refis)
• #2286: Functorise [Consistbl] (Mark Shinwell, review by
Gabriel
Radanne)
• #2291: Add [Compute_ranges] pass (Mark Shinwell, review by
Vincent
Laviron)
• #2292: Add [Proc.frame_required] and [Proc.prologue_required].
Move
tail recursion label creation to [Linearize]. Correctly
position
[Lprologue] relative to [Iname_for_debugger] operations.
(Mark
Shinwell, review by Vincent Laviron)
• #2308: More debugging information on [Cmm] terms (Mark
Shinwell,
review by Stephen Dolan)
• #7878, #8542: Replaced TypedtreeIter with tast_iterator (Isaac
"Izzy" Avram, review by Gabriel Scherer and Nicolás Ojeda Bär)
• #8598: Replace "not is_nonexpansive" by "maybe_expansive".
(Thomas
Refis, review by David Allsopp, Florian Angeletti, Gabriel
Radanne,
Gabriel Scherer and Xavier Leroy)
◊ Runtime system:
• #1725, #2279: Deprecate Obj.set_tag and Obj.truncate (Stephen
Dolan,
review by Gabriel Scherer, Damien Doligez and Xavier Leroy)
• #2075, #7729: rename _T macro used to support Unicode in the
(Windows) runtime in order to avoid compiler warning (Nicolás
Ojeda
Bär, review by Gabriel Scherer and David Allsopp)
• * #2240: Constify "identifier" in struct custom_operations
(Cedric
Cellier, review by Xavier Leroy)
• #2250: Remove extra integer sign-extension in compare
functions
(Stefan Muenzel, review by Xavier Leroy)
• * #2293: Constify "caml_named_value" (Stephen Dolan, review by
Xavier Leroy)
• #8607: Remove obsolete macros for pre-2002 MSVC support
(Stephen
Dolan, review by Nicolás Ojeda Bär and David Allsopp)
• #8656: Fix a bug in [caml_modify_generational_global_root]
(Jacques-Henri Jourdan, review by Gabriel Scherer)
• #8787, #8788: avoid integer overflow in
caml_output_value_to_bytes
(Jeremy Yallop, report by Marcello Seri)
◊ Standard library:
• #2262: take precision (.<n>) and flags ('+' and ' ') into
account in
printf %F (Pierre Roux, review by Gabriel Scherer)
• #6148, #8596: optimize some buffer operations (Damien Doligez,
reports by John Whitington and Alain Frisch, review by Jeremy
Yallop
and Gabriel Scherer)
◊ Other libraries:
• #2112: Fix Thread.yield unfairness with busy threads yielding
to
each other. (Andrew Hunter, review by Jacques-Henri Jourdan,
Spiros
Eliopoulos, Stephen Weeks, & Mark Shinwell)
• #7903, #2306: Make Thread.delay interruptible by signals again
(Xavier Leroy, review by Jacques-Henri Jourdan and Edwin
Török)
• #2248: Unix alloc_sockaddr: Fix read of uninitialized memory
for an
unbound Unix socket. Add support for receiving abstract
(Linux)
socket paths. (Tim Cuthbertson, review by Sébastien Hinderer
and
Jérémie Dimino)
• #2289: Delete the vmthreads library. This library was
deprecated in
4.08.0. (Jérémie Dimino)
• #2318: Delete the graphics library. This library is now
available as
a separate "graphics" package in opam. Its new home is:
<https://github.com/ocaml/graphics> (Jérémie Dimino, review by
Nicolas Ojeda Bar, Xavier Leroy and Sébastien Hinderer)
◊ Tools:
• #2221: ocamldep will now correctly allow a .ml file in an
include
directory that appears first in the search order to shadow a
.mli
appearing in a later include directory. (Nicolás Ojeda Bär,
review
by Florian Angeletti)
◊ Manual and documentation:
• #8757: Rename Pervasives to Stdlib in core library
documentation.
(Ian Zimmerman, review by David Allsopp)
• #7584, #8538: Document .cmt* files in the "overview" of
ocaml{c,opt}
(Oxana Kostikova, rewiew by Florian Angeletti)
• #8515: manual, precise constraints on reexported types
(Florian
Angeletti, review by Gabriel Scherer)
◊ Bug fixes:
• #7156, #8594: make top level use custom printers if they are
available (Andrew Litteken, report by Martin Jambon, review by
Nicolás Ojeda Bär, Thomas Refis, Armaël Guéneau, Gabriel
Scherer,
David Allsopp)
• #3249: ocamlmklib should reject .cmxa files (Xavier Leroy)
• #7937, #2287: fix uncaught Unify exception when looking for
type
declaration (Florian Angeletti, review by Jacques Garrigue)
• #2296: Fix parsing of hexadecimal floats with underscores in
the
exponent. (Hugo Heuzard and Xavier Leroy, review by Gabriel
Scherer)
• #8610, #8613: toplevel printing, consistent deduplicated name
for
types (Florian Angeletti, review by Thomas Refis and Gabriel
Scherer, reported by Xavier Clerc)
• #8635, #8636: Fix a bad side-effect of the -allow-approx
option of
ocamldep. It used to turn some errors into successes (Jérémie
Dimino)
• #8701, #8725: Variance of constrained parameters causes
principality
issues (Jacques Garrigue, report by Leo White, review by
Gabriel
Scherer)
• #8777(partial): fix position information in some polymorphic
variant
error messages about missing tags (Florian Angeletti, review
by
Thomas Refis)
• #8779, more cautious variance computation to avoid missing
cmis
(Florian Angeletti, report by Antonio Nuno Monteiro, review by
Leo
White)
• #8800: Fix soundness bug in extension constructor inclusion
(Leo
White, review by Jacques Garrigue)
• #8810: Env.lookup_module: don't allow creating loops (Thomas
Refis,
report by Leo White, review by Jacques Garrigue)
• #8848: Fix x86 stack probe CFI information in caml_c_call and
caml_call_gc (Tom Kelly, review by Xavier Leroy)
• #8864, #8865: Fix native compilation of left shift by
(word_size -
1) (Vincent Laviron, report by Murilo Giacometti Rocha, review
by
Xavier Leroy)
• #8862, #8871: subst: preserve scopes (Thomas Refis, report by
Leo
White, review by Jacques Garrigue)
• #8921, #8924: Fix stack overflow with Flambda (Vincent
Laviron,
review by Pierre Chambart and Leo White, report by Aleksandr
Kuzmenko)
chartjs: OCaml bindings for Chart.js charting library
═════════════════════════════════════════════════════
Archive:
<https://discuss.ocaml.org/t/ann-chartjs-ocaml-bindings-for-chart-js-charting-library/4363/1>
Alex announced
──────────────
I'm pleased to announce `chartjs', OCaml bindings for [Chart.js]
charting library and its popular extensions. The library relies
on
`js_of_ocaml' bindings for browser API and follows `js_of_ocaml'
[guides] for binding a JavaScript library.
Line, bar, horizontal bar, pie and doughnut charts are currently
supported. The bindings are not full yet, some chart types and
plugins are to be added later.
• Installation: `opam install chartjs'.
• Repository: <https://github.com/monstasat/chartjs-ocaml>
• Library sage examples:
<https://github.com/monstasat/chartjs-ocaml/tree/master/examples>
• Online documentation and examples:
<https://monstasat.github.io/chartjs-ocaml>
Some auxiliary libraries are available providing bindings for
popular
Chart.js plugins:
• `chartjs-annotation'
• `chartjs-streaming'
• `chartjs-datalabels'
• `chartjs-colorschemes'
These libraries are also available via opam.
Any feedback is highly appreciated.
[Chart.js] <http://chartjs.org>
[guides] <https://ocsigen.org/js_of_ocaml/dev/manual/bindings>
How does one print any type?
════════════════════════════
Archive:
<https://discuss.ocaml.org/t/how-does-one-print-any-type/4362/1>
Pinocchio asked
───────────────
I just want to print any type (like a print statement in
python). I am
just learning ocaml using the ocaml command interactively with
my
script basically. How do I do this?
Alex replied
────────────
You may also use the [ppx_deriving.show] plugin from the
[ppx_deriving] library. This plugin is able to generate `'a ->
string'
and `Format.formatter -> 'a -> unit' (where `'a' is the type you
want
to print) functions which can then be used for value printing.
┌────
│ type t =
│ { number : int
│ ; text : string
│ }[@@deriving show]
└────
This will produce a `show' and `pp' functions of type `t ->
string'
and `Format.formatter -> t -> unit', which can then be used as
┌────
│ let v = { number = 2; text = "Hello world"} in
│ print_endline (show v)
└────
or
┌────
│ let v = { number = 2; text = "Hello world"} in
│ let s = Format.asprintf "%a" pp v in
│ print_endline s
└────
Of course, you can always define such functions for the needed
types
by yourself.
As I can see, almost every library introducing a new type also
provides pretty-printing (kinda `pp' in this example) functions
out of
the box.
[ppx_deriving.show]
<https://github.com/ocaml-ppx/ppx_deriving#plugin-show>
[ppx_deriving] <https://github.com/ocaml-ppx/ppx_deriving>
progman also replied
────────────────────
The same basic printing as the toplevel can be had with:
[http://github.com/progman1/genprintlib ] (general value
printing in
compiled code)
Available through the official opam repository: opam install
genprint
[http://github.com/progman1/genprintlib ]
<http://github.com/progman1/genprintlib>
Ivan Gotovchits also replied
────────────────────────────
There is no such facility in OCaml. OCaml is not an interpreted
language with a dynamic type system. When a program is compiled
all
types are erased, so it is impossible in runtime to reflect a
value to
its type. And yes, as you've already pointed out, when you
interact
with OCaml using interactive toplevel there is some generic
printing
facility, but this is a very special case because you're not
really
running a program, but interactively compile it.
So, you have to accept this fact and learn how to program in
OCaml
using OCaml ways of doing things. First of all, learn how to use
the
`Format.printf' function. This is a generic function that takes
the
`format' specification and arguments and prints them, e.g.,
┌────
│ open Format
│
│ let () =
│ printf "Hello, %s world\n%!" "cruel";
│ printf "Hello, %d times!\n%!" 42
└────
As you can see, the special format specifiers, like `%s' or `%d'
specify the type of an argument. So `%d' expects one argument of
type
`int', and `%s' expects one of `string', there is also `%c' for
`char'
, `%b' for `bool' and so on.
There is also a generic `%a' specifier, which expects not one
argument, but two – a function, that will tell how to print the
argument, and the argument itself. It is used to print values of
abstract types, hence the name `%a'. There is a convention, that
modules that define abstract types also provide a function
called `pp'
which specifies how this value should be printed, e.g.,
┌────
│ let () = printf "Hello, abstract student %a\n%!" Student.pp s
└────
Where the `Student' module might be defined as
┌────
│ struct Student : sig
│ type t
│ val create : string -> int -> t
│ val pp : Format.formatter -> t -> unit
│ end = struct
│ type t = {name : string; cls : int}
│ let create name cls = {name; cls}
│ let pp ppf {name; cls} =
│ Format.fprintf ppf "%s of %d" name cls
│ end
└────
That is roughly how we print everything in OCaml :)
Interesting OCaml Articles
══════════════════════════
Archive:
<https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/50>
Yotam Barnoy said
─────────────────
<https://tarides.com/blog/2019-09-13-decompress-experiences-with-ocaml-optimization.html>
Ryan Slade also said
────────────────────
Interesting performance comparison with quite a few languages
when
writing a user space network driver:
<https://github.com/ixy-languages/ixy-languages>
Dune 2.0.0 coming soon!
═══════════════════════
Archive:
<https://discuss.ocaml.org/t/dune-2-0-0-coming-soon/4102/2>
Jérémie Dimino announced
────────────────────────
Update: after thinking about this more and working more towards
preparing Dune 2.0.0, we made the following changes compared to
this
post:
• The source code of Dune itself will remain compatible with the
last
3 released versions of OCaml rather than just the last one.
i.e. if
4.08 is the last released version of OCaml when Dune 2.0.0 is
released then Dune 2.0.0 will be guaranteed to build with
OCaml
4.06, 4.07 and 4.08. We still plan to provide an easy way to
install
Dune 2.0.0 in older opam switches
• Dune 2.0.0 will not be able to read jbuild files at all. Only
`dune
upgrade' will still be able to read them in order to upgrade
them
Old CWN
═══════
If you happen to miss a CWN, you can [send me a message] and
I'll mail
it to you, or go take a look at [the archive] or the [RSS feed
of the
archives].
If you also wish to receive it every week by mail, you may
subscribe
[online].
[Alan Schmitt]
[send me a message] <mailto:alan.schmitt at polytechnique.org>
[the archive] <http://alan.petitepomme.net/cwn/>
[RSS feed of the archives]
<http://alan.petitepomme.net/cwn/cwn.rss>
[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>
[Alan Schmitt] <http://alan.petitepomme.net/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.idyll.org/pipermail/caml-news-weekly/attachments/20190917/505a5c85/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 487 bytes
Desc: not available
URL: <http://lists.idyll.org/pipermail/caml-news-weekly/attachments/20190917/505a5c85/attachment-0001.pgp>
More information about the caml-news-weekly
mailing list