1. My ".rule" file draft with e-sexp style for GSmartMix

It looks like this now,

;;-*-lisp-*-

(begin
 ;; some debug stuffs that list the available indentifiers
 ;; (for the parser, an unknown identifier is a set/get 
 ;; over the current sink properties)
 (print "\nEvent: changed property")
 (print changed-property)

 (print "\nSink event, dumping state:")
 (print service-name)
 (print program-name)
 (print application-name)
 (print class-name)
 (print state)
 (print has-focus)
 (print volume-level)
 (print position)

 ;; these are class settings, loaded from the corresponding gconf path
 ;; if not available in gconf, set them manually  
 ;; gconf is convenient, because it is synchronized with other apps 
 ;; (configuration UI) and persistent

 ;; a class is described by:
 ;; - foreground volume level
 ;; - background volume level
 ;; - slide time (time of volume adjustments)
 ;; - a class policy
 ;;  - "LIF" Last In Foreground
 ;;  - "FIF" First In Foreground
 ;;  - "AIF" All In Foreground
 ;;  - "NA" No Adjustments (nothing will be done automatically)
 ;; - a foreground state
 ;; - a background state
 (if (not (class-load "Default"))
     (class-settings "Default" 0.7 0.6 1.0 "LIF" "playing" "paused"))
 (if (not (class-load "Voice")) 
     (begin
      (class-settings "Voice" 0.9 0.3 1.0 "FIF" "playing" "playing")
      (class-exclusion "Voice" "Music" "Movie")))
 (if (not (class-load "Event"))
     (class-settings "Event" 0.3 0.3 1.0 "AIF" "playing" "playing"))
 (if (not (class-load "Alarm"))
     (class-settings "Alarm" 1.0 0.6 1.0 "AIF" "playing" "playing"))
 (if (not (class-load "Music"))
     (begin
      (class-settings "Music" 1.0 0.6 1.0 "LIF" "playing" "paused")
      (class-exclusion "Music" "Movie")))
 (if (not (class-load "Movie"))
     (begin
      (class-settings "Movie" 1.0 0.6 1.0 "NA" "playing" "paused")
      (class-exclusion "Movie" "Music")))

 ;; this is the way an application can have a default class
 ;; if it is not set by the application itself
 (if (is class-name "Default") 
     (begin
      (if (is program-name "rhythmbox")
          (set class-name "Music"))
      (if (is program-name "totem")
          (set class-name "Movie"))
      (if (is program-name "listen")
          (set class-name "Music"))
      (if (is program-name "sound-juicer")
          (set class-name "Music"))
      (if (is program-name "ekiga")
          (set class-name "Voice"))     
      (if (is program-name "tapioca")
          (set class-name "Voice"))     
      (if (is program-name "countdowntimer")
          (set class-name "Alarm"))
      (if (is program-name "gaim2")
          (set class-name "Event"))))

 ;; I don't like the class set by the application, let me override it 
 (if (is class-name "Chat")
     (begin
      (set class-name "Voice")))

 ;; this rule is common to every class
 (if (is changed-property "state") 
     (begin
      (if (is state "playing") (set position "foreground"))
      (if (is state "ready") (set position "background"))))

 ;; let the class make the adjustments, change volume, and state
 (class-adjustments)

 ;; this is an application rule
 (if (is program-name "rhythmbox") 
     (begin
      (if (is changed-property "has-focus") 
          (if has-focus (set position "force-foreground") else (set position "background")))))

 ;; So far, all the orders are compiled, 
 ;; let's bump them up to the sink
 (apply)


 ;; further developpments might include
 ;; - priority (the queues have priority)
 ;; - metadata, meta.BuddyName, meta.Group, meta.EventName...
 ;; - ?
 )