Darryl Green wrote:

>  On a vaguely related note - I have a question about in-state
>  transitions. There is an example of a custom reaction to do this.
>  However, there is no provision for an action associated with this
>  transition. Obviously it is possible to write the action (or call it)
>  as part of the custom reaction, but this seems irregular for a
>  library that is trying to map directly from/to UML. My eyes glazed
>  over a bit trying to follow the transition handling code to add some
>  sort of an in_state_transition<> but the concept seems trivial
>  enough. Having this facility means that the same action can be used
>  for an in-state transition as for other transitions, which seems only
>  reasonable, and the similar declaration should make
>  developing/modifying a state's transitions easier.

I briefly considered this, but rejected it because in-state reactions can
relatively nicely be implemented with custom_reactions. However, it does
have advantages readability-wise. I'll work out the details and get back to
you...

>  For that matter, I
>  suppose the transition could actually specialise for the particular
>  case of a transition back to the source state, and no special
>  declaration would be needed?

No, that would be wrong. UML requires that in a self-transition the exit and
the entry action is called (see StopWatch for an example where such a
transition makes sense). This is not the case for an in-state reaction.

Regards,

Andreas


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