RE: Inheritance that can add/remove and new occam?

["O'Neill, Brian" <brian.oneill@xxxxxxxxx>]

Oyvind wrote:

> 
> When I make library code of occam programs I end up wanting some
> action to be constrained. Either I don't want to send on a 
> channel (because I have no server listening) or I don't want
> to listen on a channel (or want to listen on a channel that
> wasn't there originally). Now I use Boolean flags (parameters)
> to get something like this.
> 
> What I'm saying is: I want the local ALT to be "connected"
> with a new and dynamic branch, and perhaps even have removed
> a branch. I also want a local "!" (send) to be 
> qualified/constrained by some kind of (dynamic?) flag; perhaps
> this is saying that I do or don't want to handle some part
> of the code (no: that output channel should really disappear).
> 
I am not sure what you are requesting here.  In a truly parallel system it
is not possible to stop listening.  All input messages must be processed or
at least buffered and then over written.  In occam channels can be created
and destroyed but this requires the co-operation of both ends.  Also both
the occam and C compilers had library calls which allowed the user to guard
a channel input or output with a timeout.  If the call was not completed in
the timout period the channel was killed.


Brian


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Prof. Brian C. O'Neill        | Tel: +44 0115 848 6044
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