Why is the "Preferred" slider in the Contact Manager a variable setting?

[suzy]

I have read the FAQ for the Contact Manager, but it doesn't mention the Preferred slider.

What does it do? I guess it's something about Work vs Home, but the way it is a continuously variable setting makes me wonder if there is more to it.

[salvadordf]

Hi,

The preferred sliders can be used to indicate which email, phone number, address, etc. is the preferred one.
It's just another field in the vCard specification.

[suzy]

Thanks you, but why is it a variable slider? With this UI control, it looks like it can be set anywhere between 0 - 100%, and that it quite unusual for this purpose.It makes little sense for it to be set at 50%, but BriskBard lets me do it.

Also in the second image, all three sliders can be set to the maximum value, so which field would be the preferred Position? As a user I would expect to see a radio button, or something else that only allows one field in the group to be set as the preferred.

[salvadordf]

The specification says that the PREF parameter must be an integer between 1 and 100.
Users could be exporting or importing contacts and I decided to use a slider to avoid losing information.

https://www.rfc-editor.org/rfc/rfc6350#section-5.3

Code: Select all

   The PREF parameter is OPTIONAL and is used to indicate that the
   corresponding instance of a property is preferred by the vCard
   author.  Its value MUST be an integer between 1 and 100 that
   quantifies the level of preference.  Lower values correspond to a
   higher level of preference, with 1 being most preferred.

   When the parameter is absent, the default MUST be to interpret the
   property instance as being least preferred.

   Note that the value of this parameter is to be interpreted only in
   relation to values assigned to other instances of the same property
   in the same vCard.  A given value, or the absence of a value, MUST
   NOT be interpreted on its own.

   This parameter MAY be applied to any property that allows multiple
   instances.

   ABNF:

           pref-param = "PREF=" (1*2DIGIT / "100")
                                ; An integer between 1 and 100.

[suzy]

In Contacts, the resulting BriskBard UI (from following the vCard standard) comes across as eccentric and unconventional by using sliders. I find it difficult to imagine in practice what it means that one nickname or email address might be 30% preferred, while another is 100%. I do wonder how the RFC authors thought this flexibility would actually be applied?

Since you are following a standard, I acknowledge that it is just the way it is for BriskBard, and there are reasons for the design.

Thank you for explaining the why! TIL something.