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From: Douglas Gregor (doug.gregor_at_[hidden])
Date: 2007-05-21 10:47:05

On May 20, 2007, at 3:06 PM, Johan Torp wrote:
> I often find myself in the situation of wanting to listen to changes
> of a value type variable. I had a templated class called
> ConcreteObservable which encapsulated a get/set-able value and
> provided ways of listening to changes in the value. I.e.
> ConcreteObservable<bool> was a bool which you could get, set and
> listen to.
> 1. Does the idea of a listenable value seem sound to you or do you see
> any problems?

Looks good to me. You might consider a few minor additions:

   - A copy constructor for signalling_value, that just copies the
underlying value
   - A copy assignment operator for signalling_value, that just
copies the underlying value
   - A conversion to const T& (same functionality as get)
   - An assignment operator that takes a const T& (same functionality
as set)

> 2. Is there any existing boost code that already provides this
> functionality?

Not that I know of.

> 3. Do you see any problems with my implementation?

Looks good!

> 4. Do you have a better naming suggestion?
> Is signalling (user code would read signalling<bool>), listenable
> or signal_value perhaps better?

Did you consider "observable_value"? Or even just "observable"?

   - Doug

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