unset var [was Re: Problem and solution: Patch for new "stats" command]

[Hans-Bernhard B. <HBB...@t-...>]

Ethan Merritt wrote:
[...]

> For one thing, we don't currently have any easy way to undefine all
> these variables.  "show var GPSTAT" would show all of them, but
> "undefine GPSTAT" doesn't get rid of them.  That's fixable, I suppose,
> but I don't like the variables for another reason...

> 4) I suggest adding a mechanism for explicitly clearing out the set of
> stats calculations.  One obvious syntax is
>     reset stats

This one deserves generalization.  Unless I missed something, we 
currently don't have a command to get rid of any variable (short of 
'exit' and starting a new session), whereas the number of variables we 
have gnuplot create by itself seems to be increasing all the time (first 
"fit" results, then GPVAL_*, now possibly GPSTAT_*).

I think a generic

	unset variable {<name>| pattern <regex> | fit | stats}

command would be in order.  I would prefer 'unset' over 'reset' here 
because it matches 'show variables' a bit better than 'reset'.  It 
should probably be extended to user-defined functions, too.  And maybe 
we should even allow

	set variable <var>=<expr>
and
	set function <name>(<arguments>)=<expression>

as an optional syntax instead of the usual <var>=<expr> etc., too.