On Fri, May 14, 2004 at 10:23:45AM +0100, Peter Stephenson wrote:
> This would definitely be nice to have.

OK, I created an initial implementation of this today (it was pretty
easy, as I expected).  See if you like it.  It works in my limited
testing (i.e. a modified zcalc works quite nicely), but I may have
missed something.

> Do you think it's easy to keep the state of external files consistent
> while you do that?

I'm not sure what you mean by this.  My code isn't doing anything with
files, so the modified zcalc function still loads the .zcalc_history
file with "fc -R" and its restore function writes it out with "fc -W".
However, no fc calls are needed to save and restore the current history.

It would be possible to change my current, very simple pushhist/pophist
syntax to have pushhist optionally take some parameters to setup the new
history environment, for instance:

pushhist 200 100 ~/.zcalc_history

would be just like this shell code:

pushhist
HISTSIZE=200
SAVEHIST=100
HISTFILE=~/.zcalc_history
[[ -f $HISTFILE ]] && fc -R

And the pophist function could likewise be changed to work like this:

[[ ! -z $HISTFILE && $SAVEHIST > 0 ]] && fc -W
pophist

(Although maybe that should be "pophist -W" or something.)  However,
that may be overkill since it is so easy to code up those extra few
shell lines.

Appended is my patch.

..wayne..