Re: [Bug-AUCTeX] Apparent overlap in printing command configuration

[Ralf Angeli]

* Reuben Thomas (2010-04-20) writes:

> On 19 April 2010 20:49, Ralf Angeli <address@hidden> wrote:
>  (Not sure what Dvips does with the -P option, i.e. if it also
>> uses `lpr' or can interface directly with CUPS.)
>
> If dvips is given a printer name, it sets the output for the
> appropriate printer using config.printername, which sets an output
> pipe command (see dvips(1)). Hence, it can use lpr or CUPS, but is
> dependent on the system and user's TeX configuration. This is normally
> what you want unless you're trying to let Emacs select the printing
> system, but surely this is best left to system and user configuration
> outside Emacs rather than trying to let the Emacs user reconfigure
> everything inside Emacs.

Thanks for the info.  The printing commands might be a bit of a problem.
Up to now we've had Berkeley style commands (lpr, lpq) but those were
not available on my Debian system until I installed the cups-bsd
package.  So my impression is that the System V style commands (lp,
lpstat) might be available on a higher percentage of systems.  But
looking at how Debian handles this does not really qualify to derive a
conclusion like that.  Does anybody know which set of commands is more
widespread?

For now I've switched the commands to System V style in the defaults of
AUCTeX, but they can be changed again should somebody provide more
insight on the matter.  (Using lpq instead of lpstat would actually be
better because the former can provide output for an unnamed default
printer in contrast to the latter.)

Regarding `TeX-print-command' and `TeX-printer-list', I think I've found
out why they both have default values for the printing commands.  The
command for the "Default" entry in `TeX-printer-list' prints to an
unnamed default printer whereas the command in `TeX-print-command'
requires a name for the printer.  So with the current configuration you
can print to your default printer without having to customize anything
in AUCTeX.  If we removed the print and queue commands from the
"Default" entry in `TeX-printer-list', the user would have to customize
the printer name before printing is possible because the string
"Default" would be picked up from `TeX-printer-list' as the printer
name.  In case `TeX-printer-list' is nil, the printer name would be
derived from the environment variable PRINTER (which is not set on my
system, for example) or the string "lp" would be used as a fallback.
This does not look like a bullet-proof setup to enable printing without
customization.  So, long story short, I'd keep the commands in both
`TeX-print-command' and `TeX-printer-list'.

Regarding support for Postscript and PDF output files, that should work
now.  The printing commands got a bit more complicated in order to
achieve that.  It's a cheap-ass way to add support for that, but using
something like the predicate system for the new viewer selection code
would probably be a bit too much.

-- 
Ralf