[ESS] default pdf viewer for `ess-swv-PDF'

[Rodney Sparapani]

Martin Maechler wrote:
> unfortunately not yet.
> I know that you and others have wished for this for a while,
> and I had intended to provide it for 5.3.4, but did not get to
> that.
> 
> Let's aim to have it for 5.3.5 ....
> I'm trying to set up something which uses new variables
> ess-pref-pdfviewer and ess-pref-psviewer. 
> 
> For pdf it would try to use
> 	1) ess-pref-pdfviewer  -- if defined (is not by default)
> 
> 	2) getOption("pdfviewer") - if that's a valid file 
> 
> 	3) revert to the current list of proposed defaults.
> 
> Can I send you updated
> ess-cust.el and ess-swv.el  and you try ?
> 
> Regards, 
> Martin

Hi Martin:

It seems like we are constantly re-inventing the wheel since
alot of this stuff was written to view graphs in ESS[SAS] too.
But, I think I found out the way to handle it in a friendly
way for Unix (no idea for Windows):

(require 'mailcap)
(mailcap-mime-info "application/pdf")

The last function returns a string that can be used to launch
the viewer which gets it information from /etc/mailcap and
~/.mailcap

Rodney