This would generally give a better basis for further decisions,
while also making more concrete those things that seemed already decided??”and
perhaps revealing problems in them. Perhaps because both developers had a deep
knowledge of DSM, MetaEdit+, and state machines, we actually continued on paper
for a little while longer, looking at the possible kinds of actions.
The clearest action with a user-visible result was the control of the little LCD icons
for applications: a Stopwatch icon for when the stopwatch was running, an Alarm icon
for when the alarm was set to ring, and so on.We decided to make turning the icons on
or off an explicit action, taken when following a transition between two states.
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Another possible approach would have been to make each state contain the
information about the status of each icon, but we decided against this approach for two
reasons. First, the on/off state of the icons was persistent when their application was
exited and the next application started, and it was then unclear whether the original
application was still in some sense live and in a particular state. Second, and more
importantly, storing the icon status in each state would have meant either each state
having to store the status of each of the icons, leading to maintainability problems if
the number of icons increased, or each application only being able to control one icon,
which while initially appearing to be true, might not necessarily be so in more
complicated cases.
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