Gerhard Niklasch on Thu, 20 Nov 1997 15:56:12 +0100


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Re: From the 2.0.alpha Tutorial (1)


> > [4]--- Something else I noticed whilst playing:
> > 
> > default(compatible,0)
> > 	resets the real output format (partially: it was "e0.50"
> > before I switched from compatible=1 to 0, afterwards it was "e0.28"),
> > which I think it shouldn't do,
> 
> I'm not able to reproduce this. Can you send a minimal example ?

Uhm... I've just tried to repeat what I thought I did leading up to
that, but couldn't reproduce it either.  (Basically, I had turned on
e0.50 by doing a \format=e0.50 at compatible=1 level, and then gone
back to compatible 0, but I did a couple of things before and in
between which are gone now.  If it happens again, I'll trap it.)

> > \k
> This metacommand's behaviour is weirder than that: it does not kill
> variables... A brief history:
[...]
>   As there will soon be commands to save and restore an entire session, this
> will become pointless as well. It's of course trivial to add a parameter to
> it. What do you people think would be useful (I mean, something that you
> would actually use...) ?

What do I use it for?  I was under the impression that it cleared the
history array, and thus reduced the virtual memory footprint.  Does it now?

(And it _did_ have a strong effect in certain situations with 1.39;
due to increasing non-locality when the top of the stack and the bottom
of the history no longer fit into the L2 cache together.  Some stuff
like zetak slowed down by a factor of 3...4 when the history got long,
and was back to normal after a \k.  This is on Pentium hardware, it
may manifest itself differently or not at all on Suns etc.)

(So my main interest was actually in the precise opposite of saving
and restoring the entire session;  it was in _forgetting_ as much as
possible without the overhead of exiting and restarting the executable!)

Cheers, Gerhard

(More tutorial comments to follow, I'm on page 15 now.)