[Vm-dev] [OpenSmalltalk/opensmalltalk-vm] command line arguments use single dash prefix but also accept doubledash (#136)

[Ben Coman]

On Mon, May 8, 2017 at 12:21 AM, Eliot Miranda <eliot.miranda at gmail.com> wrote:
>
>
> IIABDFI
> Esteban rewrote the code that use -- for Pharo, preserving - for Squeak.  What's the problem??

No problem for me.  Just trying to help progress Subbu's PR.
This removes the double-dash "#ifdef PharoVM".
My question was a consequence of going forward with that,
but now I guess that part should be reverted.


Another part of the PR seems to deal with regression of Pharo --help  exit code

Pharo5$    ./pharo --help > /dev/null ; echo $?
0
Pharo6-stable-threaded-20170503$    ./pharo --help > /dev/null ; echo $?
1
Squeak5.1-16549-32bit-20160817$    ./squeak.sh -help > /dev/null ; echo $?
1

but the PR would also change "squeak --help" exit code to 0,
So perhaps that is unacceptable and either:
* the exitcode needs adding to the #ifdef,
* Pharo adopts the Squeak convention,
(although intuitively --help completes successfully implying a 0 exit code)

Here is a direct link to the diff...
https://github.com/OpenSmalltalk/opensmalltalk-vm/pull/136/files#diff-9e9b14913ecc2dd4edb6c03082408fd1L1423

cheers -ben

>
>
> _,,,^..^,,,_ (phone)
>
> On May 7, 2017, at 8:50 AM, Ben Coman <notifications at github.com> wrote:
>
> @bencoman requested changes on this pull request.
>
> Can we have some discussion on [vm-dev] about the flexibility of Squeakers to use double-hyphen options as default?
>
> ________________________________
>
> In platforms/unix/vm/sqUnixMain.c:
>
> > @@ -1467,7 +1464,8 @@ static int vm_parseArgument(int argc, char **argv)
>
>    /* vm arguments */
>
> -  if      (!strcmp(argv[0], VMOPTION("help"))) { usage(); return 1; }
> +  if      (!strcmp(argv[0], VMOPTION("help"))) { usage(0);         /*NOTREACHED*/}
>
> Would it be better to shift the exit() out of usage(), so that real code affection execution flow is used here rather than a comment. i.e. here... { usage(); exit(0) } ??
>
> ________________________________
>
> In platforms/unix/vm/sqUnixMain.c:
>
> > @@ -1721,7 +1719,7 @@ static void usage(void)
>    printf("\nAvailable drivers:\n");
>    for (m= modules;  m->next;  m= m->next)
>      printf("  %s\n", m->name);
> -  exit(1);
> +  exit(exitValue);
>
> Refactor the exit() out to the caller ??
>
> ________________________________
>
> In platforms/unix/vm/sqUnixMain.c:
>
> > @@ -1819,7 +1817,8 @@ static void parseArguments(int argc, char **argv)
>        if (n == 0) /* option not recognised */
>   {
>    fprintf(stderr, "unknown option: %s\n", argv[0]);
> -  usage();
> +  usage(1);
> +  /*NOTREACHED*/
>
> Same as above, refactor exit out of usage() ? i.e. here...
> usage();
> exit(1)
>
> ________________________________
>
> In platforms/unix/vm/sqUnixMain.c:
>
> >  {
>    struct SqModule *m= 0;
>    printf("Usage: %s [<option>...] [<imageName> [<argument>...]]\n", argVec[0]);
>    printf("       %s [<option>...] -- [<argument>...]\n", argVec[0]);
> +  printf("options begin with single -, but -- prefix is silently accepted\n");
>
> The problem is that single-hyphen default is then what is advised by --help. Why isn't it preferable to conform to Unix conventions [1] "The GNU double-hyphen option leader was chosen so that traditional single-letter options and GNU-style keyword options could be unambiguously mixed on the same command line. "
> [1] http://www.catb.org/~esr/writings/taoup/html/ch10s05.html
>
> The single-hyphen could be silently accepted for backward compatibility. Maybe better would be a deprecated message, but perhaps that could adversely affect existing scripts(?).
>
> How do Squeakers feel about that?
>
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