Re: Candidate stem-and-leaf plot function

[Daniel J Sebald]

On 01/26/2013 04:42 PM, Michael D. Godfrey wrote:
> Dan,
>
> I thought about the ability to produce a figure in PDF (or other) format.
>
> Attached is a simple function which does this using enscript. I am
> not sure if enscript is a current dependency. but if so some other
> format conversion program could be used.

I installed enscript.  enscript appears to be a GNU program, so the GNU 
folks probably would be happy it's used.  I would say in this case, 
given the limited nature of stemleaf() at this point that rather than a 
dependency, do a system check in the script file for the program using 
the version option

[sebald]$ enscript -V
GNU Enscript 1.6.5.2
Copyright (C) 1995-2003, 2007, 2008, 2009, 2010 Free Software 
Foundation, Inc.
etc.

So before calling the enscript command, first check for its existence 
and if the system() command is an error instead of a sensible output 
about GNU Enscript, then issue a message to the Octave command line 
about requiring and installing GNU Enscript.  If everything checks out, 
then issue the command via system() as you've done.


>  This avoids the complexity
> of the full plotting path.

True, but it doesn't offer features such as titles and keys, but yes 
that would be a bit more of a project than desired at the moment. 
Regarding Carnë's comment, I would consider it a plot.  I can recall the 
days when dot-matrix printers were used to create even Cartesian plots, 
as crude as that was.  We have histogram plots

 -- Function File:  hist (Y, X, NORM)
     Produce histogram counts or plots.

and the stem-and-leaf plot is similar.  One could imagine dual-data 
plots where next to one another are color coded stems for the different 
data sets just like a histogram might have color coded, interleaved 
bins--and a key to go along with it.


>  Again, of course, this function could be made
> more elaborate. enscript has LOTS of options. These could be passed
> as an argument in show_plot(). If this approach lots OK I can add that
> or other options, like any of the other output formats provided by
> enscript.

I think it is a good start to use Enscript.  However, I'd suggest rather 
than "show_plot()", simply incorporate that code into the "stemleaf" 
function with option "enscript".  Some options would be:

"enscript"
   "text"
   "pdf"
     "trim"
   "ps"
     "trim"
   "eps"
     "trim"

Rather than creating a text, pdf and ps I think just one of formats is 
fine.  Don't want to make things too messy in the user's directory.  The 
"trim" option would put tight bounding boxes around the output. 
Enscript doesn't appear to have that, but one of the PostScript 
utilities such as ps2pdf, ps2eps, should.

If you get things to that point, a nice self-contained routine that 
provides a bit of output, it's a good start.


> Also, just to make sure it is noticed I changed the name to: stemleaf()

OK, seems like the natural choice.

Dan