[jamming] Command built-in questions (was Re: Executing shell command, save results to variable)

[Diane Holt]

Rather than start adding more builtins, why not just use the Strtok rule. It
actually does work fine.

Diane

On 3/23/07, David Turner <david at freetype.org> wrote:
>
> Hi,
>
> > AFAIK, it is been problem on Win32 for an ages, and no one provided an
> > good alternative for unix implementation. I didn't used it on Win32 side
> and
> > not sure what are pros/cons of current implementation, but after quick
> > search I found some alternative on qt list:
> > http://lists.trolltech.com/qt-interest/1999-09/thread00282-0.html
> >
> > I am not able to decipher german comments, but hoping this can be good
> > starting point.
> >
> That's not too bad. Fortunately, I have some code, written several years
> ago
> that implement exactly what we need, i.e. a cross-platform "spawn"
> function that
> can be used to control the inputs and outputs of external programs.
>
> My code did work on Win32, OS/2 and Unix, and I'm currently stripping it
> down
> to use it in Jam. The Win32 code already works pretty fine, but could be a
> bit
> simpler since we don't need to do a lot of the fancy things that were part
> of
> the initial requirements. I think I'll have something good to show next
> week.
>
> By the way, what does "popen" does with the non-redirected standard
> streams of the
> executed commands on Unix. For now, I have the choice of implementing any
> of the
> following, I don't have made any decision yet:
>
> - redirect stdin to /dev/zero
> - redirect stdin to /dev/nul   (blocking)
> - redirect stderr to stdout
> - redirect stderr to /dev/null
> - keep stdin and stderr as they are, they're inherited by the child
> process
>
> Do any of you guys can think of a good rationale for thinking about a
> consistent
> behaviour. I plan to implement the same one on all platforms.
>
> Any VMS hacker to implement "popen" or something like that as well ?
>
> Apart from that, I think that "lines" should be a reasonable default. I'd
> rather
> see a new "Split" built-in to perform the lines-to-word separation than
> add
> arguments to the "Command" built-in
>
> Regards,
>
> - David
>
> of the executed commands
>
> > > - is there some serious use to the "mixed" and "lines" cases ? we
> really don't want
> > >   to turn Jamfiles into parsing programs, don't we.
> >
> > For "lines" (thought): for example we know that program outputs our
> > interested data on second or third line (gcc -v for example). But this
> > is probably better to be handled via external script, keeping jam source
> > simple.
> >
> > > - which default behaviour would you prefer ? (I'm for "words", but
> YMMV)
> >
> > I am for "words" too (and only "words" :)).
> >
> > --
> > Sanel
> > _______________________________________________
> > jamming mailing list  -  jamming at perforce.com
> > http://maillist.perforce.com/mailman/listinfo/jamming
> _______________________________________________
> jamming mailing list  -  jamming at perforce.com
> http://maillist.perforce.com/mailman/listinfo/jamming
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://maillist.perforce.com/pipermail/jamming/attachments/20070323/93ec9e4b/attachment.html