[Toybox] [Nommu] Week ending June 27ish.

[Isaac Dunham]

On Sun, Jun 28, 2015 at 10:57:00PM -0400, Rich Felker wrote:
> On Sun, Jun 28, 2015 at 06:15:26PM -0500, Rob Landley wrote:
> > > Are there perhaps any other shells that work on nommu? It would be
> > > nice to be able to put off toysh until you have time to do a really
> > > good job on it rather than rushing it because there's nothing else you
> > > can use...
> > 
> > Eh, I can do it in stages. And setting up another shell is effort (and
> > natural test/use cases) that's _not_ going into toysh development, so
> > I'd rather do it right than do other things that get thrown away.
> > 
> > That said, sure, http://www.cod5.org/archive/ links to es and pdksh for
> > example, and uclibc had like 5 of them (all kinda crappy if I recall).
> > None really an improvement on hush in terms of actually building stuff.
> 
> I'm pretty sure pdksh conforms to POSIX (at least the 1992 version) so
> it's probably sufficient for running portable scripts including all
> configure scripts. I know your goal is much higher (bash
> compatibility) but it sounds like pdksh could get you a working
> environment until you finish toysh, with little or no effort spent on
> the temporary solution.

Some comments:
- pdksh is a lot closer to bash compatability than "conforms to the 1992
edition of POSIX" would imply.
This is partly because bash copied many of its feaures from ksh.

- there *are* configure scripts that need bash--I don't remember the
software, but I have run into them. Of course, I've also seen configure
scripts that used ed and software that required the old csh (the one
that got "&&" and "||" backwards) to build.
I never looked into exactly what was required, though: I just rm'd
anything like that.
configure scripts used to be portable, but nowdays they often just try.

- pdksh works almost everywhere, but this is portability the hard way:
there are special cases for every *nix of the time, as well as *every*
other OS (yes, DOS and EMX support included...and probably VMS as well).
And the code is every bit as ugly as one would infer from that, and
quite possibly more so.

So theoretically, there probably is a code path that works with nommu.
But it will almost certainly be nontrivial to even identify it, let
alone get nommu properly detected and support automatically built.

- OpenBSD ships a version of ksh that has been minimally altered as
their /bin/sh; this is the basis for loksh. It has been modified
only minimally.

I think it's entirely sensible for Rob to not poke at pdksh; getting it
to work right on all Aboriginal's platforms is likely to be a large
drain. If someone else wants to fix it up and patch Aboriginal until
they can pass the smoketests on all platforms, accepting their patch 
to use pdksh in Aboriginal might be sensible; but before that, it's
too big a project for a temporary gain.


Thanks,
Isaac Dunham



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