Returning a variant property array from Detect is undesirable.

[digitaltrails]

The Detect method is returning an array of properties. The properties vary in type, which means they must be typed Variant. On the client side the Variant properties must be explicitly unpacked to native types - this is an undesirable requirement for such a simple interface.

The alternative to returning arrays of properties have their own issues:

• Return individual output arrays. Each of array would hold one kind of value: an array of display-id, an array of edid_id, etcetera. This has the advantage that the output parameters are named and are therefore self-describing. The downside is that it seems a bit contrived and hacky.
• Return an array of structs. The downside is that the struct elements would be unnamed and it would be up to the client to "know" which one is which - ugly because it's not self-describing. A mitigation might be to also pass back an array of field-names describing what's in the struct.

I investigated whether an struct of non-variant properties was valid, for example `({si}{ss}{sq})', but it seems not.

[digitaltrails]

After experimenting with a python interface I went with the second described solution. The Detect() method now returns structs. Python receives the structs as tuples, so they're pretty easy to work with. By adding a property the returns the names of the structure members, python can easily turned the unnamed tuples into named tuples:

bus = SessionMessageBus()

ddcutil_proxy = bus.get_proxy(
    "com.ddcutil.libddcutil.DdcutilServer",  # The bus name
    "/com/ddcutil/libddcutil/DdcutilObject",  # The object name
)

# Create a namedtuple that matches the attributes returned by the detect method
DetectedAttributes = namedtuple("DetectedAttributes", ddcutil_proxy.AttributesReturnedByDetect)

# Call detect to get back a list of unnamed tuples, one for each VDU
number_detected, list_of_displays, status, errmsg = ddcutil_proxy.Detect()
print(f"{number_detected=} {status=} {errmsg=}\n")
print(list_of_displays)

# Reform unnamed tuples into a list of namedtuples (optional, for convenience)
vdu_list = [DetectedAttributes(*vdu) for vdu in list_of_displays]
print(vdu_list)