practicality of custom config

[Michael Zucchi]

Morning,

From the manual:

   "It is also /customizable/: users can /derive/ specialized package
   definitions from existing ones, including from the command line (see
   Package Transformation Options
   
<https://guix.gnu.org/manual/en/html_node/Package-Transformation-Options.html#Package-Transformation-Options>).
   "


But in reality how practical would it be to create a system which for 
example doesn't include pulseaudio?  I'm using slackware 64and it 
provides this option so ideally I don't want guix dragging it back in.

Looking through the package definitions it looks like considerable 
effort: either editing or using code to edit (aka deriving) every 
package that uses it.  For deriving changes it would require internal 
knowledge of the source package definition and would thus be rather 
fragile and difficult to maintain.

This is one example but there may be other system-wide options that one 
might want to customise in a similar way to services, is there a 
mechanism for this?

 Z