Musings on an Erlang GUI System. [long, very long] ramble... ramble ...

Bob.Smart <>
Fri Feb 14 06:46:57 CET 2003


> Liveliness  in that checkboxes, buttons, anything
> really can have its own independent, concurrent,
> behavior. 

Often a GUI is a view into a universe where the user
of the GUI is not the only entity that can influence
the state of that universe. To put it more simply:
the GUI shows you a snapshot but what is shown might
change even before you press any buttons, etc.

Take for example a pulldown list (or a scrolled list
for that matter) where the user can make a choice.
While you think about which choice to make someone
else might do something that increases or decreases
that choice. [For example while you try to decide where
to sit at a theatre someone else might grab some of
the seats.] I'd like to see the list (or theatre seat
layout or whatever) be updated as it happens: not have
me pick something and get an error message [though that
might still happen]. It is important that things don't
change position while I get ready to click: things that
become unavailable should just go grey; new things 
should appear at the the end or in a special place
[or a message appears saying "new entries, reload to
see them"].

Outlook is an example of a really bad GUI that lacks
"liveness". If the network is busy or Exchange is
busy the GUI goes dead and you can't even minimize
it. If Microsoft can produce such a thing then it
is not surprising that many GUIs are deficient in
this way, but it is time we got it right.

Bob



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