On Mon, Mar 12, 2007 at 12:14:08AM +0100, Martin Neubauer wrote:
>Specifically, there are two arguments supporting the change. First, it isn't
>really a new feature -- it just makes one already present more general (with
>a striking resemblance to the for loop.) Second, it doesn't break scripts in a
>harmful way (old scripts still run, new scripts run in an old rc abort -- if
>a correctly written script runs successfully it does what was intended in
>either case.)

This is entirely beside the point. Breaking old scripts is the least of 
the issues. The point is that there's little value in altering rc, 
compared to writing a new shell. Compare mash and sh on Inferno and 
you'll see what I mean, as I've said. If mash had simply been extended, 
there would be either a slightly more or sligtly less crufty mash, 
instead of sh.

If rc is to be updated, it should simply be replaced with something 
better. If Plan 9 is a research OS, as has been suggested in this 
thread, then why are we to add features to an old shell, rather than 
rethinking it? The former has nothing to do with research. I'm too tired 
to argue saliently, but the point is that if rc is lacking, we've been 
shown better ways already, and they should be instrumented or improved 
upon properly, not simply hacked onto old cruft.

Again, this is exactly how UNIX ended up how it is today, and why Plan 9 
is not UNIX.

-- 
Kris Maglione

An easily-understood, workable falsehood is more useful
than a complex, incomprehensible truth.