Adding support for multiple wiper systems as an overlay

overlays/README.md

@@ -0,0 +1,12 @@
+# OVERLAYS
+
+This directory contains overlays for VSS. Use of overlays is a new concept for VSS.
+The overlays in this folder shall currently be seen as examples only, and are not part of the official VSS specification.
+
+## Profiles 
+
+Larger overlays to adapt VSS to a specific vehicle category, like motorbikes.
+
+## Extensions
+
+Smaller overlays typically to be applied after applying profiles (if any).

overlays/extensions/dual_wiper_systems.vspec

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+#
+# (C) 2022 Robert Bosch GmbH
+#
+# Overlay to extend wiper system to support multiple instances
+# Dependencies to other overlays: None
+# Known conflicts with other overlays: None
+#
+Vehicle:
+  type: branch
+
+Vehicle.Body:
+  type: branch
+  description: All body components.
+
+Vehicle.Body.Windshield:
+  type: branch
+  instances: ["Front", "Rear"]
+  description: Windshield signals.
+
+Vehicle.Body.Windshield.Wiping:
+  type: branch
+  description: Windshield wiper signals.
+
+# Standard VSS does not specify instances
+# This overlay specifies two instances, Primary and Secondary
+
+Vehicle.Body.Windshield.Wiping.System:
+  type: branch
+  instances: [Primary, Secondary]
+  description: Signals to control behavior of wipers in detail.
+  comment:     These signals are typically not directly available to the user/driver of the vehicle.
+               Primary refers to the primary wiper system for the windshield.
+               Secondary refers to the secondary wiper system for the same windshield.

spec/Body/Body.vspec

@@ -112,15 +112,11 @@ Windshield.Wiping.Intensity:
 
 Windshield.Wiping.System:
   type: branch
-#  instances: [Primary, Secondary]
   description: Signals to control behavior of wipers in detail.
                By default VSS expects only one instance.
   comment:     These signals are typically not directly available to the user/driver of the vehicle.
-               A vehicle may have multiple mechanically disconnected wiper systems serving the same windshield.
-               If that is the case for a vehicle it is recommended to add
-               instance declarations for Primary and Secondary, possibly in a layer.
-               Primary then refers to the primary wiper system for the windshield.
-               Secondary then refers to the secondary wiper system for the same windshield.
+               The overlay in overlays/extensions/dual_wiper_systems.vspec can be used to modify this branch
+               to support two instances; Primary and Secondary.
 
 #include WiperSystem.vspec Windshield.Wiping.System