A plotting style to be used in the context of "set table" that would allow filling the table with an arbitrary number of columns.
My current way of using the xyerrorbars style seems a bit unorthodox, as not to call it a misuse.
i.e.:
gp> set table
gp> plot "datafile" using 0:(sin($1+$3)):($0*1.547):4:6 with tablestyle
it would probably be nice to also be able to control the delimiter used in the table, and the handling of invalid datapoints (i.e. to omit the point completely instead of adding "u" or "o" ).
Letting the plot command check for NaN values and handle them appropriately can of course be done already, like
plot "" using (($2==0?NaN:$1/$2)
For this, it would also be nice if the tablestyle allowed for string values in output variables. Don´t know if this would be hard to implement.
Final ideas: Add an "append" parameter to the "set table" command, which would make it possible to write a custom comment to the file with "set print". Then it should be possible to switch off the standard comment.
I'm still thinking about this one.
Meanwhile, note that the equivalent of your "append" example is already possible:
set table "foo"
plot ... whatever
unset table
set print "| cat >> foo"
print "# Closing remarks"
unset print
Now in CVS.