Character encodings in PostScript driver

[Ethan M. <merritt@u.washington.edu>]

There are 50+ character encodings currently registered for use
on the internet <http://www.iana.org/assignments/character-sets>
and I have no idea how many more that are not so registered.
They are all perfectly legitimate, but I think it is totally unreasonable
that any substantial fraction of them get hard-coded into gnuplot's
PostScript terminal driver.

I propose that we back out all of the in-line character encodings
from post.trm, and instead have a general mechanism of loading
any requested encoding from an external file.  If you recall, I
coded up a simple patch to do this in the run-up to version 4
because it was needed in order to reduce the total size of 
the terminal driver to the point it could be built for 16-bit DOS/Win.

The idea was dropped when we decided it was OK to
abandon 16-bit support altogether, but I still think it's a good
idea and deserves to be revisited.

The chief benefit from this is that new encodings could be 
added without patching or rebuilding gnuplot from source;
you would just have to place an appropriately named file
in the path specified by some environmental variable,
e.g. GNUPLOT_PSFILES.

As I recall, the only real objection at the time was a fear that
these external files containing the character encoding info
would get lost under Windows because there is no standard
directory in which to put such things.  I don't really have much
sympathy with limiting gnuplot's options just because Windows
is poorly designed.  

Are there other objections in addition to that one?

-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195