Re: Configuring output drivers

[Ben Pfaff]

John Darrington <address@hidden> writes:

> Some questions which spring to mind are:
>
> * How do we make sure that the GUI has an appropriately configured
> driver?

One way would be to export the function configure_driver_line
from output/output.c.  Then the GUI could call this function with
an appropriate specification either in place of or in addition to
calling outp_read_devices.

> * We have to have a "well known" pathname for the file associated with
> its output.  What should this pathname be?

pspp.list is what the command-line UI uses by default.  I won't
claim that this is the best possible.  Perhaps pspp.txt or
pspp.text would be better, because it gives other software a
chance to roughly guess its format from the file name.

It may be a good idea to keep the default output names for the
command-line and graphical UIs the same.  (In the end, though, it
might turn out that the command-line UI should really be sending
its output to stdout instead of a file.)

> * It the GUI starts with an existing output file, then what action
> should be taken? Delete the file ? Ignore the existing content?

I think that appending to the existing content, if any, would be
a reasonable default.  It would be nice to have a menu item to
purge the contents of the output file, I guess.

Oh, and I think everyone realizes this, but I just want to
re-emphasize it: the existing output engine will need to be
replaced in any case, so the goal here is not to get perfect
output or great output, but just to have something that makes the
GUI usable, at least to a minimal extent, for running analysis
procedures.

After the 0.6.0 release I think it'll be time to start discussing
the output engine seriously.  I've done a lot of thinking, and
made several experiments, and I think I know what will work well.
I *definitely* know several approaches that will not work well.
-- 
"[Modern] war is waged by each ruling group against its own subjects,
 and the object of the war is not to make or prevent conquests of territory,
 but to keep the structure of society intact."
--George Orwell, _1984_