[cwn] Attn: Development Editor, Latest OCaml Weekly News

Alan Schmitt alan.schmitt at polytechnique.org
Mon Jun 25 23:49:52 PDT 2018


Hello

Here is the latest OCaml Weekly News, for the week of June 19 to 26,
2018.


Native and JS stubs with js_of_ocaml
════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/native-and-js-stubs-with-js-of-ocaml/2164/1]

  /Paul Biggar asked:/


  Some of the functions and modules I'm using in my native executable,
  are not able to compile to JS using js_of_ocaml. For example, Nocrypto
  cannot compile to JS, and some of the Core.Time functions are not in
  Core_kernel.Time. However, there are straightforward JS equivalents I
  could use.

  How can I write these stubs so that the same library can compile both
  JS and native? For example, I have a library that could call either
  `Nocrypto.Hash.SHA284.digest' or a JS file called crypto.js with
  sha384_digest, depending on the compilation target. How would I set
  jbuilder up to compile that?

  Related question: if I want a type that is one thing when doing our JS
  compilation (perhaps a JS object) and another thing (probably a
  Core.Time.t) for native compilation, how do I do that. I guess I want
  to create a MyTime.t that abstracts over those two types, but I don't
  know where to get started with this.


  /Christophe Riolo suggested:/


  I do not know if what you want to do can be achieved with js_of_ocaml
  but you might be interested in checking Bucklescript
  ([https://bucklescript.github.io/]) which enables linking to JS
  functions as exernals. I do not know how it works with jbuilder
  though, it seems to have its own build system.

  As for your second question, no idea, but there is, linked to
  Bucklescript again, `bsb-native' that enables compiling to ocaml
  instead of JS ([https://github.com/bsansouci/bsb-native]) I'd /expect/
  that you can give alternatives depending on the backend.


  /Thomas Gazagnaire also replied:/


  There is work-in progress to support that out of the box in
  jbuilder/dune, it's called [Library Variants]. The idea is to define a
  commun signature for various implementations, depending on the
  backends you want to use. Tip: we are very interested to have this for
  [MirageOS] :slight_smile:

  That feature is not planned for dune 1.0, but you can already achieve
  something similar by tweaking a bit your build system: see
  [https://github.com/diml/variants-workaround] for a template. The
  trick is to compile the common mli with `-no-keep-locs' on 4.06.1 and
  to choose the right implementation at link time.


  /Paul Biggar then said:/


  Thanks, this is super helpful! I haven't quite got the JS side
  working, but the ocaml side and structure works well.

  For anyone else whose doing a similar thing, here's how it played out:

  We had a simple layout:
  • lib: almost all the code
  • main: a few binaries, mostly 6-7 lines, using lib
  • test: tested lib code

  We now have:
  • libtarget: target-specific functions. Has no implementation
  • libtarget.ocaml: implementation for libtarget for the backend
  • libtarget.js: implementation for libtarget for the frontend
  • libbackend: all server code, depends on libtarget and
    libtarget.ocaml
  • libexecution: the code we wanted to share between client and
    server. Depends on libtarget
  • libfrontend: all client code. Depends on libtarget and libtarget.js
  • main: makes binaries from libbackend
  • js: makes js from libfrontend
  • test: tests js code

  Quick question: why is `--no-keep-locs' important?


  /Thomas Gazagnaire then said:/


  That's great! We are in the process of chaning some of the mirage
  libraries to use that scheme too, to have both a portable OCaml and an
  efficient C implementation for [checksums] and [hashes]. We should add
  a JS backend too at one point too.

  Using `--keep-locs' allows to get better error messages. It adds
  locations to the cmi files, which make them non relocatable. See
  [https://github.com/ocaml/ocaml/pull/1219] for the rational of turning
  that on per default and the related discussion.


  /nick betteridge replied to the original question:/


  There's also [gen_js_api] for generating ocaml bindings for javascript




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


[Library Variants] https://github.com/ocaml/dune/issues/136

[MirageOS] https://mirage.io

[checksums] https://github.com/dinosaure/checkseum

[hashes] https://github.com/mirage/digestif

[gen_js_api] https://github.com/LexiFi/gen_js_api


OCaml 4.07.0+rc1
════════════════

  Archive:
  [https://sympa.inria.fr/sympa/arc/caml-list/2018-06/msg00032.html]

  /Gabriel Scherer announced:/


  The release of OCaml version 4.07.0 is imminent. We have created a
  release candidate for your testing pleasure. Please download the
  sources, compile, install, and test your favourite software with it,
  and let us know whether it works for you.

  We want to know about any show-stopping bugs, especially in the
  compilation and installation phases.

  This release candidate is available as an opam switch 4.07.0+rc1, and
  as source archive at this address:
  [https://caml.inria.fr/pub/distrib/ocaml-4.07/]

  Happy hacking,

  – Gabriel Scherer for the OCaml team.

  Some highlights of this release are:

  • The way the standard library modules are organized internally has
    changed (GPR#1010):
    1. the List module (for example) is now named Stdlib__list
    2. a new Stdlib module contains a series of aliases such as `module
       List = Stdlib__list'
    3. the Stdlib module is implicitly opened when type-checking OCaml
       programs (as Pervasives previously was), so that Stdlib.List can
       be accessed as just List, as before.

    This should be invisible to most users, although it is possible that
    some tools show the Stdlib. or Stdlib__ prefixes in messages. (You
    might want to report these situations as usability bugs.) The change
    prevents standard library modules from conflicting with end-user
    filenames (please avoid stdlib.ml and the stdlib__ prefix); we may
    introduce new standard library modules in the future with less fear
    of breaking user code. In particular, Float (GPR#1638) and Seq
    (GPR#1002) modules have now been added to the standard library.

  • The error messages caused by various typing errors have been
    improved to be easier to understand, in particular for
    beginners. (GPR#1505, GPR#1510)

    For example,
    ┌────
    │ # while 1 do () done;;
    │         ^
    │ Error: This expression has type int but an expression was expected of type
    │        bool
    └────
    now adds the extra explanation
    ┌────
    │ because it is in the condition of a while-loop
    └────

  • Effort has been made to reduce the compilation time of flambda
    programs, and the size of the produced `.cmx' files when using the
    -Oclassic optimisation level. (GPR#1401, GPR#1455, GPR#1627,
    GPR#1665, GPR#1667)

  • The HTML manual has benefited from various style improvements and
    should look visually nicer than previous editions. (GPR#1741,
    GPR#1757, GPR#1767)

    A preview of this new manual is available at
    [http://caml.inria.fr/pub/docs/manual-ocaml-4.07/] For comparison,
    the 4.06 manual uses the old style:
    [http://caml.inria.fr/pub/docs/manual-ocaml-4.06/]

  • Since 4.01, it is possible to select a variant constructor or record
    field from a sub-module that is not opened in the current scope, if
    type information is available at the point of use. This now also
    works for GADT constructors. (GPR#1648)

  • The GC should handle the accumulation of custom blocks in the minor
    heap better; this solves some memory-usage issues observed by code
    which allocates a lot of small custom blocks, typically small
    bigarrays (GPR#1476)

  The full changelog is included below.

  (Changes that can break existing programs are marked with a "*")


Language features:
──────────────────

  • MPR#6023, GPR#1648: Allow type-based selection of GADT constructors
    (Thomas Refis and Leo White, review by Jacques Garrigue and Gabriel
    Scherer)

  • GPR#1546: Allow empty variants (Runhang Li, review by Gabriel
    Radanne and Jacques Garrigue)


Standard library:
─────────────────

  • MPR#4170, GPR#1674: add the constant `Float.pi'.  (Christophe
    Troestler, review by Damien Doligez)

  • MPR#6139, GPR#1685: Move the Bigarray module to the standard
    library. Keep the bigarray library as on overlay adding the
    deprecated map_file functions (Jérémie Dimino, review by Mark
    Shinwell)

  • MPR#7690, GPR#1528: fix the float_of_string function for hexadecimal
    floats with very large values of the exponent.  (Olivier Andrieu)

  • GPR#1002: add a new `Seq' module defining a list-of-thunks style
    iterator. Also add `{to,of}_seq' to several standard modules.
    (Simon Cruanes, review by Alain Frisch and François Bobot)

  • * GPR#1010: pack all standard library modules into a single module
    Stdlib which is the default opened module (Stdlib itself includes
    Pervasives) to free up the global namespace for other standard
    libraries, while still allowing any OCaml standard library module to
    be referred to as Stdlib.Module). This is implemented efficiently
    using module aliases (prefixing all modules with Stdlib__,
    e.g. Stdlib__string).  (Jérémie Dimino, David Allsopp and Florian
    Angeletti, review by David Allsopp and Gabriel Radanne)

  • GPR#1637: String.escaped is faster and does not allocate when called
    with a string that does not contain any characters needing to be
    escaped.  (Alain Frisch, review by Xavier Leroy and Gabriel Scherer)

  • GPR#1638: add a Float module.  (Nicolás Ojeda Bär, review by Alain
    Frisch and Jeremy Yallop)

  • GPR#1697: Tune [List.init] tailrec threshold so that it does not
    stack overflow when compiled with the Js_of_ocaml backend.  (Hugo
    Heuzard, reviewed by Gabriel Scherer)


Other libraries:
────────────────

  • MPR#7745, GPR#1629: Graphics.open_graph displays the correct window
    title on Windows again (fault introduced by 4.06 Unicode changes).
    (David Allsopp)

  • * GPR#1406: Unix.isatty now returns true in the native Windows ports
    when passed a file descriptor connected to a Cygwin PTY. In
    particular, compiler colors for the native Windows ports now work
    under Cygwin/MSYS2.  (Nicolás Ojeda Bär, review by Gabriel Scherer,
    David Allsopp, Xavier Leroy)

  • GPR#1451: [getpwuid], [getgrgid], [getpwnam], [getgrnam] now raise
    Unix error instead of returning [Not_found] when interrupted by a
    signal.  (Arseniy Alekseyev, review by Mark Shinwell and Xavier
    Leroy)

  • GPR#1477: raw_spacetime_lib can now be used in bytecode.  (Nicolás
    Ojeda Bär, review by Mark Shinwell)

  • GPR#1533: (a) The implementation of Thread.yield for system thread
    now uses nanosleep(1) for enabling better preemption.  (b)
    Thread.delay is now an alias for Unix.sleepf.  (Jacques-Henri
    Jourdan, review by Xavier Leroy and David Allsopp)


Compiler user-interface and warnings:
─────────────────────────────────────

  • MPR#7663, GPR#1694: print the whole cycle and add a reference to the
    manual in the unsafe recursive module evaluation error message.
    (Florian Angeletti, report by Matej Košík, review by Gabriel
    Scherer)

  • GPR#1166: In OCAMLPARAM, an alternative separator can be specified
    as first character (instead of comma) in the set ":|; ," (Fabrice Le
    Fessant)

  • GPR#1358: Fix usage warnings with no mli file (Leo White, review by
    Alain Frisch)

  • GPR#1428: give a non dummy location for warning 49 (no cmi found)
    (Valentin Gatien-Baron)

  • GPR#1491: Improve error reporting for ill-typed applicative functor
    types, F(M).t.  (Valentin Gatien-Baron, review by Florian Angeletti
    and Gabriel Radanne)

  • GPR#1496: Refactor the code printing explanation for unification
    type errors, in order to avoid duplicating pattern matches (Armaël
    Guéneau, review by Florian Angeletti and Gabriel Scherer)

  • GPR#1505: Add specific error messages for unification errors
    involving functions of type "unit -> _" (Arthur Charguéraud and
    Armaël Guéneau, with help from Leo White, review by Florian
    Angeletti and Gabriel Radanne)

  • GPR#1510: Add specific explanation for unification errors caused by
    type constraints propagated by keywords (such as if, while, for…)
    (Armaël Guéneau and Gabriel Scherer, original design by Arthur
    Charguéraud, review by Frédéric Bour, Gabriel Radanne and Alain
    Frisch)

  • GPR#1515: honor the BUILD_PATH_PREFIX_MAP environment variable to
    enable reproducible builds (Gabriel Scherer, with help from Ximin
    Luo, review by Damien Doligez)

  • GPR#1534: Extend the warning printed when (​*​) is used, adding a hint
    to suggest using ( * ) instead (Armaël Guéneau, with help and review
    from Florian Angeletti and Gabriel Scherer)

  • GPR#1552, GPR#1577: do not warn about ambiguous variables in guards
    (warning 57) when the ambiguous values have been filtered by a
    previous clause (Gabriel Scherer and Thomas Refis, review by Luc
    Maranget)

  • GPR#1554: warnings 52 and 57: fix reference to manual detailed
    explanation (Florian Angeletti, review by Thomas Refis and Gabriel
    Scherer)

  • GPR#1618: add the -dno-unique-ids and -dunique-ids compiler flags
    (Sébastien Hinderer, review by Leo White and Damien Doligez)

  • GPR#1649 change compilation order of toplevel definitions, so that
    some warnings emitted by the bytecode compiler appear more in-order
    than before.  (Luc Maranget, advice and review by Damien Doligez)

  • GPR#1806: add linscan to OCAMLPARAM options (Raja Boujbel)


Code generation and optimizations:
──────────────────────────────────

  • MPR#7630, GPR#1401: Faster compilation of large modules with
    Flambda.  (Pierre Chambart, report by Emilio Jesús Gallego Arias,
    Pierre-Marie Pédrot and Paul Steckler, review by Gabriel Scherer and
    Leo White)

  • MPR#7630, GPR#1455: Disable CSE for the initialization function
    (Pierre Chambart, report by Emilio Jesús Gallego Arias, review by
    Gabriel Scherer and Xavier Leroy)

  • GPR#1370: Fix code duplication in Cmmgen (Vincent Laviron, with help
    from Pierre Chambart, reviews by Gabriel Scherer and Luc Maranget)

  • GPR#1486: ARM 32-bit port: add support for ARMv8 in 32-bit mode,
    a.k.a. AArch32.  For this platform, avoid ITE conditional
    instruction blocks and use simpler IT blocks instead (Xavier Leroy,
    review by Mark Shinwell)

  • GPR#1487: Treat negated float comparisons more directly (Leo White,
    review by Xavier Leroy)

  • GPR#1573: emitcode: merge events after instructions reordering
    (Thomas Refis and Leo White, with help from David Allsopp, review by
    Frédéric Bour)

  • GPR#1606: Simplify the semantics of Lambda.free_variables and
    Lambda.subst, including some API changes in bytecomp/lambda.mli
    (Pierre Chambart, review by Gabriel Scherer)

  • GPR#1613: ensure that set-of-closures are processed first so that
    other entries in the let-rec symbol do not get dummy approximations
    (Leo White and Xavier Clerc, review by Pierre Chambart)

  • * GPR#1617: Make string/bytes distinguishable in the bytecode.
    (Hugo Heuzard, reviewed by Nicolás Ojeda Bär)

  • GPR#1627: Reduce cmx sizes by sharing variable names (Flambda only)
    (Fuyong Quah, Leo White, review by Xavier Clerc)

  • GPR#1665: reduce the size of cmx files in classic mode by droping
    the bodies of functions that will not be inlined (Fuyong Quah,
    review by Leo White and Pierre Chambart)

  • GPR#1666: reduce the size of cmx files in classic mode by droping
    the bodies of functions that cannot be reached from the module block
    (Fuyong Quah, review by Leo White and Pierre Chambart)

  • GPR#1686: Turn off by default flambda invariants checks.  (Pierre
    Chambart)

  • GPR#1707: Add [Closure_origin.t] to trace inlined functions to
    prevent infinite loops from repeatedly inlining copies of the same
    function.  (Fu Yong Quah)

  • GPR#1740: make sure startup.o is always linked in when using
    "-output-complete-obj". Previously, it was always linked in only on
    some platforms, making this option unusable on platforms where it
    wasn't (Jérémie Dimino, review by Sébastien Hinderer and Xavier
    Leroy)


Runtime system:
───────────────

  • MPR#6411, GPR#1535: don't compile everything with -static-libgcc on
    mingw32, only dllbigarray.dll and libbigarray.a. Allows the use of
    C++ libraries which raise exceptions.  (David Allsopp)

  • MPR#7100, GPR#1476: trigger a minor GC when custom blocks accumulate
    in minor heap (Alain Frisch, report by talex, review by Damien
    Doligez, Leo White, Gabriel Scherer)

  • GPR#1431: remove ocamlrun dependencies on curses/terminfo/termcap C
    library (Xavier Leroy, review by Daniel Bünzli)

  • GPR#1478: The Spacetime profiler now works under Windows (but it is
    not yet able to collect profiling information from C stubs).
    (Nicolás Ojeda Bär, review by Xavier Leroy, Mark Shinwell)

  • GPR#1483: fix GC freelist accounting for chunks larger than the
    maximum block size.  (David Allsopp and Damien Doligez)

  • GPR#1526: install the debug and instrumented runtimes
    (lib{caml,asm}run{d,i}.a) (Gabriel Scherer, reminded by Julia
    Lawall)

  • GPR#1563: simplify implementation of LSRINT and ASRINT (Max
    Mouratov, review by Frédéric Bour)

  • GPR#1644: remove caml_alloc_float_array from the bytecode primitives
    list (it's a native code primitive) (David Allsopp)

  • GPR#1701: fix missing root bug in GPR#1476 (Mark Shinwell)

  • GPR#1752: do not alias function arguments to sigprocmask (Anil
    Madhavapeddy)

  • GPR#1753: avoid potential off-by-one overflow in debugger socket
    path length (Anil Madhavapeddy)


Tools:
──────

  • MPR#7643, GPR#1377: ocamldep, fix an exponential blowup in presence
    of nested structures and signatures (e.g. "include struct …
    include(struct … end) … end") (Florian Angeletti, review by Gabriel
    Scherer, report by Christophe Raffalli)

  • MPR#7687, GPR#1653: deprecate -thread option, which is equivalent to
    -I +threads.  (Nicolás Ojeda Bär, report by Daniel Bünzli)

  • MPR#7710: `ocamldep -sort' should exit with nonzero code in case of
    cyclic dependencies (Xavier Leroy, report by Mantis user
    baileyparker)

  • GPR#1537: boot/​ocamldep is no longer included in the source
    distribution; boot/ocamlc -depend can be used in its place.
    (Nicolás Ojeda Bär, review by Xavier Leroy and Damien Doligez)

  • GPR#1585: optimize output of "ocamllex -ml" (Alain Frisch, review by
    Frédéric Bour and Gabriel Scherer)

  • GPR#1667: add command-line options -no-propt, -no-version, -no-time,
    -no-breakpoint and -topdirs-path to ocamldebug (Sébastien Hinderer,
    review by Damien Doligez)

  • GPR#1695: add the -null-crc command-line option to ocamlobjinfo.
    (Sébastien Hinderer, review by David Allsopp and Gabriel Scherer)

  • GPR#1710: ocamldoc, improve the 'man' rendering of subscripts and
    superscripts.  (Gabriel Scherer)

  • GPR#1771: ocamdebug, avoid out of bound access (Thomas Refis)


Manual and documentation:
─────────────────────────

  • MPR#7613: minor reword of the "refutation cases" paragraph (Florian
    Angeletti, review by Jacques Garrigue)

  • PR#7647, GPR#1384: emphasize ocaml.org website and forum in README
    (Yawar Amin, review by Gabriel Scherer)

  • PR#7698, GPR#1545: improve wording in OCaml manual in several
    places, mostly in Chapter 1.  This addresses the easier changes
    suggested in the PR.  (Jim Fehrle, review by Florian Angeletti and
    David Allsopp)

  • GPR#1540: manual, decouple verbatim and toplevel style in code
    examples (Florian Angeletti, review by Gabriel Scherer)

  • GPR#1556: manual, add a consistency test for manual references
    inside the compiler source code.  (Florian Angeletti, review by
    Gabriel Scherer)

  • GPR#1647: manual, subsection on record and variant disambiguation
    (Florian Angeletti, review by Alain Frisch and Gabriel Scherer)

  • GPR#1702: manual, add a signature mode for code examples (Florian
    Angeletti, review by Gabriel Scherer)

  • GPR#1741: manual, improve typesetting and legibility in HTML output
    (steinuil, review by Gabriel Scherer)

  • GPR#1757: style the html manual, changing type and layout (Charles
    Chamberlain, review by Florian Angeletti, Xavier Leroy, Gabriel
    Radanne, Perry E. Metzger, and Gabriel Scherer)

  • GPR#1765: manual, ellipsis in code examples (Florian Angeletti,
    review and suggestion by Gabriel Scherer)

  • GPR#1767: change html manual to use relative font sizes (Charles
    Chamberlain, review by Daniel Bünzli, Perry E. Metzger, Josh
    Berdine, and Gabriel Scherer)

  • GPR#1779: integrate the Bigarray documentation into the main manual.
    (Perry E. Metzger, review by Florian Angeletti and Xavier Clerc)


Type system:
────────────

  • MPR#7611, GPR#1491: reject the use of generative functors as
    applicative (Valentin Gatien-Baron)

  • MPR#7706, GPR#1565: in recursive value declarations, track static
    size of locally-defined variables (Gabriel Scherer, review by Jeremy
    Yallop and Leo White, report by Leo White)

  • MPR#7717, GPR#1593: in recursive value declarations, don't treat
    unboxed constructor size as statically known (Jeremy Yallop, report
    by Pierre Chambart, review by Gabriel Scherer)

  • MPR#7767, GPR#1712: restore legacy treatment of partially-applied
    labeled functions in 'let rec' bindings.  (Jeremy Yallop, report by
    Ivan Gotovchits, review by Gabriel Scherer)

  • * MPR#7787, GPR#1652, GPR#1743: Don't remove module aliases in
    `module type of' and `with module'.  The old behaviour can be
    obtained using the `[@remove_aliases]' attribute.  (Leo White and
    Thomas Refis, review by Jacques Garrigue)

  • GPR#1468: Do not enrich type_decls with incoherent manifests (Thomas
    Refis and Leo White, review by Jacques Garrigue)

  • GPR#1469: Use the information from [@@immediate] annotations when
    computing whether a type can be [@@unboxed] (Damien Doligez, report
    by Stephan Muenzel, review by Alain Frisch)

  • GPR#1513: Allow compilation units to shadow sub-modules of
    Pervasives. For instance users can now use a largeFile.ml file in
    their project.  (Jérémie Dimino, review by Nicolas Ojeda Bar, Alain
    Frisch and Gabriel Radanne)

  • GPR#1516: Allow float array construction in recursive bindings when
    configured with -no-flat-float-array (Jeremy Yallop, report by
    Gabriel Scherer)

  • GPR#1583: propagate refined ty_arg to Parmatch checks (Thomas Refis,
    review by Jacques Garrigue)

  • GPR#1609: Changes to ambivalence scope tracking (Thomas Refis and
    Leo White, review by Jacques Garrigue)

  • GPR#1628: Treat reraise and raise_notrace as nonexpansive.  (Leo
    White, review by Alain Frisch)

  • * GPR#1778: Fix Soundness bug with non-generalized type variable and
    local modules.  This is the same bug as MPR#7414, but using local
    modules instead of non-local ones.  (Leo White, review by Jacques
    Garrigue)


Compiler distribution build system
──────────────────────────────────

  • MPR#5219, GPR#1680: use 'install' instead of 'cp' in install scripts
    (Gabriel Scherer, review by Sébastien Hinderer)

  • MPR#7679: make sure .a files are erased before calling ar rc,
    otherwise leftover .a files from an earlier compilation may contain
    unwanted modules (Xavier Leroy)

  • GPR#1571: do not perform architecture tests on 32-bit platforms,
    allowing 64-bit back-ends to use 64-bit specific constructs (Xavier
    Clerc, review by Damien Doligez)


Internal/compiler-libs changes:
───────────────────────────────

  • MPR#7738, GPR#1624: Asmlink.reset also resets lib_ccobjs/ccopts
    (Cedric Cellier, review by Gabriel Scherer)

  • GPR#1488, GPR#1560: Refreshing parmatch (Gabriel Scherer and Thomas
    Refis, review by Luc Maranget)

  • GPR#1502: more command line options for expect tests (Florian
    Angeletti, review by Gabriel Scherer)

  • GPR#1511: show code at error location in expect-style tests, using
    new Location.show_code_at_location function (Gabriel Scherer and
    Armaël Guéneau, review by Valentin Gatien-Baron and Damien Doligez)

  • GPR#1519, GPR#1532, GRP#1570: migrate tests to ocamltest (Sébastien
    Hinderer, review by Gabriel Scherer, Valentin Gatien-Baron and
    Nicolás Ojeda Bär)

  • GPR#1520: more robust implementation of Misc.no_overflow_mul (Max
    Mouratov, review by Xavier Leroy)

  • GPR#1557: Organise and simplify translation of primitives (Leo
    White, review by François Bobot and Nicolás Ojeda Bär)

  • GPR#1567: register all idents relevant for reraise (Thomas Refis,
    review by Alain Frisch and Frédéric Bour)

  • GPR#1586: testsuite: 'make promote' for ocamltest tests (The new
    "-promote" option for ocamltest is experimental and subject to
    change/removal).  (Gabriel Scherer)

  • GPR#1619: expect_test: print all the exceptions, even the unexpected
    ones (Thomas Refis, review by Jérémie Dimino)

  • GPR#1621: expect_test: make sure to not use the installed stdlib
    (Jérémie Dimino, review by Thomas Refis)

  • GPR#1646 : add ocamldoc test to ocamltest and migrate ocamldoc tests
    to ocamltest (Florian Angeletti, review by Sébastien Hinderer)

  • GPR#1663: refactor flambda specialise/inlining handling (Leo White
    and Xavier Clerc, review by Pierre Chambart)

  • GPR#1679 : remove Pbittest from primitives in lambda (Hugo Heuzard,
    review by Mark Shinwell)

  • * GPR#1704: Make Ident.t abstract and immutable.  (Gabriel Radanne,
    review by Mark Shinwell)


Bug fixes
─────────

  • MPR#4499, GPR#1479: Use native Windows API to implement Sys.getenv,
    Unix.getenv and Unix.environment under Windows.  (Nicolás Ojeda Bär,
    report by Alain Frisch, review by David Allsopp, Xavier Leroy)

  • MPR#5250, GPR#1435: on Cygwin, when ocamlrun searches the path for a
    bytecode executable file, skip directories and other non-regular
    files, like other Unix variants do.  (Xavier Leroy)

  • MPR#6394, GPR#1425: fix fatal_error from Parmatch.get_type_path
    (Virgile Prevosto, review by David Allsopp, Thomas Refis and Jacques
    Garrigue)

  • * MPR#6604, GPR#931: Only allow directives with filename and at the
    beginning of the line (Tadeu Zagallo, report by Roberto Di Cosmo,
    review by Hongbo Zhang, David Allsopp, Gabriel Scherer, Xavier
    Leroy)

  • MPR#7138, MPR#7701, GPR#1693: Keep documentation comments even in
    empty structures and signatures (Leo White, Florian Angeletti,
    report by Anton Bachin)

  • MPR#7178, MPR#7253, MPR#7796, GPR#1790: Make sure a function
    registered with "at_exit" is executed only once when the program
    exits (Nicolás Ojeda Bär and Xavier Leroy, review by Max Mouratov)

  • MPR#7391, GPR#1620: Do not put a dummy method in object types
    (Thomas Refis, review by Jacques Garrigue)

  • PR#7660, GPR#1445: Use native Windows API to implement Unix.utimes
    in order to avoid unintended shifts of the argument timestamp
    depending on DST setting.  (Nicolás Ojeda Bär, review by David
    Allsopp, Xavier Leroy)

  • MPR#7668: -principal is broken with polymorphic variants (Jacques
    Garrigue, report by Jun Furuse)

  • MPR#7680, GPR#1497: Incorrect interaction between Matching.for_let
    and Simplif.simplify_exits (Alain Frisch, report and review by
    Vincent Laviron)

  • MPR#7682, GPR#1495: fix [@@unboxed] for records with 1 polymorphic
    field (Alain Frisch, report by Stéphane Graham-Lengrand, review by
    Gabriel Scherer)

  • MPR#7695, GPR#1541: Fatal error: exception Ctype.Unify(_) with field
    override (Jacques Garrigue, report by Nicolás Ojeda Bär)

  • MPR#7704, GPR#1564: use proper variant tag in non-exhaustiveness
    warning (Jacques Garrigue, report by Thomas Refis)

  • MPR#7711, GPR#1581: Internal typechecker error triggered by a
    constraint on self type in a class type (Jacques Garrigue, report
    and review by Florian Angeletti)

  • MPR#7712, GPR#1576: assertion failure with type abbreviations
    (Thomas Refis, report by Michael O'Connor, review by Jacques
    Garrigue)

  • MPR#7747: Type checker can loop infinitly and consumes all computer
    memory (Jacques Garrigue, report by kantian)

  • MPR#7751, GPR#1657: The toplevel prints some concrete types as
    abstract (Jacques Garrigue, report by Matej Kosik)

  • MPR#7765, GPR#1718: When unmarshaling bigarrays, protect against
    integer overflows in size computations (Xavier Leroy, report by
    Maximilian Tschirschnitz, review by Gabriel Scherer)

  • MPR#7760, GPR#1713: Exact selection of lexing engine, that is
    correct "Segfault in ocamllex-generated code using 'shortest'" (Luc
    Maranget, Frédéric Bour, report by Stephen Dolan, review by Gabriel
    Scherer)

  • MPR#7769, GPR#1714: calls to Stream.junk could, under some
    conditions, be ignored when used on streams based on input channels.
    (Nicolás Ojeda Bär, report by Michael Perin, review by Gabriel
    Scherer)

  • MPR#7793, GPR#1766: the toplevel #use directive now accepts
    sequences of ';;' tokens. This fixes a bug in which certain files
    accepted by the compiler were rejected by ocamldep.  (Nicolás Ojeda
    Bär, report by Hugo Heuzard, review by Hugo Heuzard)

  • GPR#1517: More robust handling of type variables in mcomp (Leo White
    and Thomas Refis, review by Jacques Garrigue)

  • GPR#1530, GPR#1574: testsuite, fix 'make parallel' and 'make one
    DIR=…' to work on ocamltest-based tests.  (Runhang Li and Sébastien
    Hinderer, review by Gabriel Scherer)

  • GPR#1550, GPR#1555: Make pattern matching warnings more robust to
    ill-typed columns (Thomas Refis, with help from Gabriel Scherer and
    Luc Maranget)

  • GPR#1614: consider all bound variables when inlining, fixing a
    compiler fatal error.  (Xavier Clerc, review by Pierre Chambart, Leo
    White)

  • GPR#1622: fix bug in the expansion of command-line arguments under
    Windows which could result in some elements of Sys.argv being
    truncated in some cases.  (Nicolás Ojeda Bär, review by Sébastien
    Hinderer)

  • GPR#1623: Segfault on Windows 64 bits when expanding wildcards in
    arguments. (Marc Lasson, review by David Allsopp, Alain Frisch,
    Sébastien Hinderer, Xavier Leroy, Nicolas Ojeda Bar)

  • GPR#1661: more precise principality warning regarding record fields
    disambiguation (Thomas Refis, review by Leo White)

  • GPR#1687: fix bug in the printing of short functor types "(S1 -> S2)
    -> S3" (Pieter Goetschalckx, review by Gabriel Scherer)

  • GPR#1722: Scrape types in Typeopt.maybe_pointer (Leo White, review
    by Thomas Refis)

  • GPR#1755: ensure that a bigarray is never collected while reading
    complex values (Xavier Clerc, Mark Shinwell and Leo White, report by
    Chris Hardin, reviews by Stephen Dolan and Xavier Leroy)

  • GPR#1764: in byterun/memory.c, struct pool_block, use C99 flexible
    arrays if available (Xavier Leroy, review by Max Mouratov)

  • GPR#1774: ocamlopt for ARM could generate VFP loads and stores with
    bad offsets, rejected by the assembler.  (Xavier Leroy, review by
    Mark Shinwell)

  • GPR#1808: handle `[@inlined]' attributes under a module constraint
    (Xavier Clerc, review by Leo White)

  • GPR#1810: use bit-pattern comparison when meeting float
    approximations (Xavier Clerc, report by Christophe Troestler, review
    by Nicolás Ojeda Bär and Gabriel Scherer)




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


Omod 0.0.2
══════════

  Archive:
  [https://sympa.inria.fr/sympa/arc/caml-list/2018-06/msg00033.html]

  /Daniel Bünzli announced:/


  > P.S. Currently `omod` doesn't work with opam system compilers.

  omod 0.0.2 has been released and solves this problem.

  See [0] for all the changes. 

  Best, 

  Daniel

  [0]: [https://github.com/dbuenzli/omod/blob/master/CHANGES.md#v002-2018-06-19-zagreb]




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


HTTP2 implementation in OCaml
═════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/http2-implementation-in-ocaml/2172/1]

  /Anurag Soni announced:/


  After the discussion on another thread
  ([https://discuss.ocaml.org/t/advantages-of-ocaml-over-rust/2112/44?u=anuragsoni]),
  I have started some work towards exploring the types needed to start
  an implementation of HTTP2. This might not be the best code as I'm
  still making my way through learning OCaml. Feedback and/or
  contributions are very welcome. For now i'll be reading the HTTP2
  specs ([https://httpwg.org/specs/rfc7540.html]) and looking at some
  existing implementations. (Rust, Dart and Haskell are a few that have
  existing implementations)

  [https://github.com/anuragsoni/h2]




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


dokeysto: a simple key-value store in ocaml
═══════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-dokeysto-a-simple-key-value-store-in-ocaml/2173/1]

  /UnixJunkie announced:/


  Dokeysto provides a persistent hash table of string keys to string
  values.  Optionally, if you use the right module (like
  Dokeysto.Db.RWZ), values will be compressed using LZ4 before being
  written to disk.

  The interface is here:
  [https://github.com/UnixJunkie/dokeysto/blob/master/src/db.mli]

  An example/test is here:
  [https://github.com/UnixJunkie/dokeysto/blob/master/src/test.ml]


  /UnixJunkie then added:/


  To install it:
  ┌────
  │ opam update && opam install dokeysto
  └────




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


CLI prompt package
══════════════════

  Archive: [https://discuss.ocaml.org/t/cli-prompt-package/2181/1]

  /Nadeem Bitar asked:/


  Is anyone aware of a package that helps display a multi-select prompt
  from a CLI app?

  Here is a screenshot of an example of what I'm trying to accomplish.

  [https://discourse-cdn-sjc2.com/standard11/uploads/ocaml/original/2X/e/ecb9bf1fecf5c0ec9846b27d1df8f2f46a82f35e.png]


  /Matthieu Dubuget suggested:/


  You may have a look at [notty].

  Not sure that it is what you are looking for…


  /Hezekiah Carty also suggested:/


  [lambda-term] is another option.  lambda-term is used by [utop]. notty
  probably has a smaller dependency footprint.




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


[notty] https://github.com/pqwy/notty

[lambda-term] https://github.com/diml/lambda-term

[utop] https://github.com/diml/utop


Any Intermediate/Advanced OCaml MOOCs?
══════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/any-intermediate-advanced-ocaml-moocs/2182/1]

  /Phil Tomson asked:/


  I know there's an introductory OCaml MOOC. I'm wondering if there's a
  more advanced class that digs deeply into Modules, Functors, GADTs and
  the like?

  Anything already out there or in planning?


  /Levi Roth suggested:/


  I don't know if it's a MOOC per se, but @yallop teaches an "Advanced
  Functional Programming" course at Cambridge that has its materials
  online: [https://www.cl.cam.ac.uk/teaching/1718/L28/materials.html]


  /Marcello Seri also suggested:/


  That is quite interesting, but a bit hard without the frontal lectures
  imho.  Depending on your experience, you may want to have a look at
  the types course first:
  [https://www.cl.cam.ac.uk/teaching/1718/Types/]




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


atd 2.0.0
═════════

  Archive: [https://discuss.ocaml.org/t/ann-atd-2-0-0/2193/1]

  /Rudi Grinberg announced:/


  On behalf of the atd team, I'm pleased to announce the release of atd
  2.0. This release is a major version bump because it contains a couple
  of breaking changes:

  • Removal of the tag_field field. E.g. `<json tag_field=..>.'
  • Removal of `untyped' field.

  These features now have superior alternatives:

  • An `open_enum' option to read unknown strings into a catch all
    variant
  • An adapter mechanism to manipulate json on the fly before it is
    passed on to the atd generated readers/writers.

  I'll refer to the manual for more thorough descriptions of the
  feature:
  • [https://atd.readthedocs.io/en/latest/atdgen.html?highlight=open_enum#field-open-enum]
  • [https://atd.readthedocs.io/en/latest/atdgen.html?highlight=open_enum#field-adapter-ocaml]

  The manual is also quite new, and the team is working on polishing the
  documentation. We are happy to hear your comments.




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


Ocaml Github Pull Requests
══════════════════════════

  /Gabriel Scherer and the editor compiled this list:/


  Here is a sneak peek at some potential future features of the Ocaml
  compiler, discussed by their implementers in these Github Pull
  Requests.

  • Add "finally" function to Pervasives
    ([https://github.com/ocaml/ocaml/pull/1855])




  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――


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/

-- 
OpenPGP Key ID : 040D0A3B4ED2E5C7
Monthly Athmospheric CO₂, Mauna Loa Obs. 2018-05: 411.25, 2017-05: 409.65
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 528 bytes
Desc: not available
URL: <http://lists.idyll.org/pipermail/caml-news-weekly/attachments/20180626/d8c36a1d/attachment-0001.pgp>


More information about the caml-news-weekly mailing list