From: Markus Mottl <mottl@miss.wu-wien.ac.at>
Message-Id: <199907012235.AAA05846@miss.wu-wien.ac.at>
Subject: Re: Sys.argv with interpreter and compiler
To: Xavier.Leroy@inria.fr (Xavier Leroy)
Date: Fri, 2 Jul 1999 00:35:44 +0100 (MET DST)
In-Reply-To: <19990701193222.56286@pauillac.inria.fr> from "Xavier Leroy" at Jul 1, 99 07:32:22 pm
> > Wouldn't it be logically more consistent to pass the truncated array
> > of arguments to the script under the interpreter so that the program
> > always gets its name on index 0 - no matter whether it is compiled
> > or interpreted?
>
> Yes, it would be more consistent, but that's exactly what it does
> currently. At least, that's what a quick test under Linux shows.
>
> > - With the current version it gets the name of the
> > interpreter on this position.
>
> That's surprising. On which operating system do you see this
> behavior? The treatment of argv[0] in C w.r.t. #! scripts differs
> between various versions of Unix, but we tried to compensate for this
> in the OCaml bytecode interpreter.
My explanation may probably be misconceived - maybe "interpreted" means
"interpreted by the byte code interpreter" to you whereas I use "compiled"
for byte code and native code and "interpreted" if I call the interactive
toplevel with a file argument.
Anyhow, I have made a test on two systems (Intel/Linux and Alpha/Digital
Unix) with ocaml-2.02-2. Both systems behaved exactly the same way, but
I got three different outputs for the three ways to execute the program.
The output of this program (bla.ml):
print_endline Sys.argv.(0)
yielded:
interpreted: /home/mottl/mysys/bin/ocaml
compiled to byte code: ./bla
compiled to native code: bla
The difference between the byte code and native code version is probably
not so big a problem. But it would be useful for the development process
if the "interpreted" version would pass the arguments at the same index
in the argument vector.
As far as I remember, making OCaml (at least under Unix) a "true"
scripting-language (=with human-readable "#!"-scripts) is not so easy to
achieve: only binaries may be used as interpreters of "#!"-scripts, which
is not currently possible with the way the toplevel "ocaml" is designed -
it needs to be a byte code file. Are there already any convenient ways
around this problem?
Using byte code for scripting is not so comfortable and I think that
OCaml would give a wonderful language for "true" scripting...
Best regards,
Markus Mottl
-- Markus Mottl, mottl@miss.wu-wien.ac.at, http://miss.wu-wien.ac.at/~mottl
This archive was generated by hypermail 2b29 : Sun Jan 02 2000 - 11:58:23 MET