Re: [Caml-list] ocamlbuild on Windows and bash vs. cmd

[Gerd Stolpmann <info@gerd-stolpmann.de>]

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This is also what omake does. Pipes, redirections, and even a number of
commands like rm, cp, ls are completely implemented inside omake, so
that everything works on Unix and Windows the same. I guess this is the
only way to get to a uniform build system, at least if you don't want
to depend on 3rd-party tools like Cygwin.

Gerd

Am Donnerstag, den 06.10.2016, 18:45 +0100 schrieb Jeremie Dimino:
> I don't have an opinion on using cmd in ocamlbuild, but I have been
> looking at similar things for jenga recently. With jenga the actions
> generated by the rules are of the form (prog, args) and when one
> wants
> to to do something more complicated, they have to manually build a
> shell command. In the Jane Street rules we are using bash.
> 
> Going through bash is often frustrating, even on Unix. Moreover for
> the public release of Jane Street packages I'd like to avoid relying
> too much on bash as it has often been a source of problems in the
> past.
> 
> The solution I'm aimed at is to have the jenga rules produce actions
> using a small DSL allowing pipes and other things and interpret this
> DSL without the use of a third-party shell, i.e. just using system
> calls and threads.
> 
> It's still a work in progress but I already have the backend part
> working [1]. It's aimed at being portable on Windows. The code for
> Windows is written but not yet tested, I plan to do it at some point.
> 
> I imagine that it shouldn't be too use this in ocamlbuild if the [Sh]
> constructor was removed and replaced by a few other constructors to
> express pipes, redirections, etc...
> 
>   [1] https://github.com/janestreet/shexp
> 
> On Thu, Oct 6, 2016 at 2:38 PM, Soegtrop, Michael
> <michael.soegtrop@intel.com> wrote:
> > 
> > Dear OCaml users and developers,
> > 
> > 
> > 
> > I looked into the fact that ocamlbuild requires bash/cygwin to run.
> > Actually
> > it does very little use of bash and I think cmd + ln + rm would
> > work quite
> > well.
> > 
> > 
> > 
> > From comments in various list I understood that people had issues
> > with
> > escaping for cmd. I agree that this is a bit nasty, but not rocket
> > science
> > either. I guess the main issue is that for cmd not only space and
> > tab are
> > command argument separators, but also equal (=), comma (,) and
> > semicolon
> > (;). So for cmd a=b,c;d is the same as a b c d which is the same as
> > a , = ,
> > b =;= c==d. Essentially cmd treats unquoted pieces as sed ‘s/[\t
> > =,;]+/ /g’.
> > If a name contains any of these characters, one has to quote it for
> > cmd, but
> > not for bash. Since = and , are not that uncommon in file names, I
> > guess
> > this resulted in issues.
> > 
> > 
> > 
> > BUT cmd splits the command line only into command names, complete
> > argument
> > lists and file names for redirection. That is if you call e.g.
> > ocamlc, cmd
> > just replaces shell variables and extracts the executable name, but
> > does not
> > split up the argument list into individual pieces. bash on Windows
> > does this
> > neither, because (afaik) Windows has at the lowest level no
> > mechanism to
> > pass individual arguments to an executable. The command gets a
> > string and
> > splitting this string and even globing is the business of the
> > executable. So
> > it is rather odd that this behaves substantially different for bash
> > and for
> > cmd. The only thing which needs to be quoted properly are command
> > names and
> > file names of redirections.
> > 
> > 
> > 
> > There might be issue with shell special characters. There are those
> > which
> > are not allowed in file names “\/:*?<>| and those allowed in
> > filenames &().
> > I guess those not allowed in filenames don’t need any special
> > treatment,
> > since one can’t do that much with them except their special shell
> > use. The
> > other 3 one should be escape with ^. There is no way to quote shell
> > special
> > characters with cmd – they must be escaped with ^.
> > 
> > 
> > 
> > The only real issue is that some people seem to use build rules
> > with “real”
> > bash stuff in it – well if you do this I guess you anyway have a
> > cygwin
> > around.
> > 
> > 
> > 
> > So I wonder if it would be appreciated by the community to have an
> > ocamlbuild (e.g. as a configure option) which uses cmd instead of
> > bash. I
> > think if one does the escaping properly, this should be good for
> > the large
> > majority of projects out there.
> > 
> > 
> > 
> > Ocamlc seems to run fine without cygwin, but I didn’t test other
> > tools like
> > ocamllex or menhir as yet. Are there known issues?
> > 
> > 
> > 
> > Best regards,
> > 
> > 
> > 
> > Michael
> > 
> > 
> > 
> > 
> > 
> > Intel Deutschland GmbH
> > Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
> > Tel: +49 89 99 8853-0, www.intel.de
> > Managing Directors: Christin Eisenschmid, Christian Lamprechter
> > Chairperson of the Supervisory Board: Nicole Lau
> > Registered Office: Munich
> > Commercial Register: Amtsgericht Muenchen HRB 186928
> 
> 
> -- 
> Jeremie
> 
-- 
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Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de
My OCaml site:          http://www.camlcity.org
Contact details:        http://www.camlcity.org/contact.html
Company homepage:       http://www.gerd-stolpmann.de
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