[augeas-devel] Avoiding wheel reinvention with dpkg.cfg, and setting empty things.

[Robin Lee Powell]

On Mon, Dec 29, 2008 at 09:54:13PM -0800, David Lutterkort wrote:
> > - ----------------
> > 
> > (* Parsing /etc/dpkg/dpkg.cfg *)
> > 
> > module Dpkg =
> >   autoload xfm
> > 
> >   let sep_tab = Util.del_ws_tab
> >   let sep_spc = Util.del_ws_spc
> >   let eol = del /[ \t]*\n/ "\n"
> > 
> >   let comment = Util.comment
> >   let empty   = Util.empty
> > 
> >   let word = /[^,# \n\t]+/
> > 
> >   let bare_option = [ label "bare_option" . store word ]
> > 
> >   let valued_option = [ label "value_option" . store word ] . sep_spc .
> >                         [ label "value" . store word ]
> >   let record = [ seq "option" . ( bare_option | valued_option ) . eol ]
> 
> Why don't you use the name of the option as a key and store the value
> for that option as the value of the tree node ? Something along the
> lines of (untested):
> 
>         let record = [ key word . (sep_spc . store word)? . eol ]
>         
> That would producea much more compact and readable tree.

Because I have no idea what I'm doing.  :)  I just grabbed the fstab
lens and flailed.

> One obvious improvement, assuming that dpkg.cfg uses a fixed set of
> option names, 

FSVO "fixed"; I assume it changes from version to version.

> > I have no idea what the "seq" keyword actually *does*, for
> > example.
> 
> Does http://www.augeas.net/docs/lenses.html not provide enough info ? 

Ah.  I misunderstood what that page was for.  Yes, that helps.

> There's also some more docs on the Wiki, e.g.
> http://www.augeas.net/page/Creating_a_lens_step_by_step

I didn't see that one.  I assumed that
http://www.augeas.net/docs/writing-schemas.html (with the big "TO BE
CONTINUED") was all I had to work with.  Perhaps you should link
that wiki page from the documentation section?

-Robin

-- 
They say:  "The first AIs will be built by the military as weapons."
And I'm thinking:  "Does it even occur to you to try for something
other than the default outcome?" -- http://shorl.com/tydruhedufogre
http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/