'data-file' as a string variable in the "plot" command

[Constantine N. <ne...@at...>]

String variables in GnuPlot are associated with various commands like "label",
"title", 'key', etc. This is all nice since one can even use Latex extensions.
Unfortunately the "plot" command doesn't accept the name of the 'data-file' as
a string variable. In a way it is kind of hard-wired into this most important 
of commands, around which the whole system is built. Very often (at least in 
my scripts!) I need to change the names (or only part of the names!) of my 
input data files, which are being processed for plotting, on the fly directly 
in my script. But due to the fact that I can not use a string variable as the 
name of a data file I have to go outside the GnuPlot system, run a Sequential 
Editor on the GnuPlot script in order to change the names of the data-files, 
and then return back to GnuPlot. Quite often this is nuisance and time 
consuming.

Therefore, my advice to the developers of future versions of this very useful 
plotting and visualization system is to incorporate, if possible, the option 
of using 'data-file' names as string variables in the generic "plot" command.
The other option of the possibility of concatenating various string variables 
for that purpose, as is done in high level compiled languages like FORTRAN and 
C/C++, will be also very welcome.

Any comment from the developers will be highly appreciated. Thanks a lot.

Best regards,
Constantine Nenkov