[isabelle-dev] NEWS

[Lawrence Paulson]

I think your point is that somebody who spent a lot of effort making their code work with a development snapshot could be wasting their time, because the next release could be as different and require everything to be converted again.

I still think there is no harm using the mailing list to advise users that sets are going to change back to their former behaviour. At the very least, we can advise users to avoid using mem_def and confine themselves to the set primitives.
Larry

On 5 Jan 2012, at 16:49, Makarius wrote:

> When taking a development snapshot users will get the full load of accidental incompatibilities, not just the 'a set thing, and usually get into a pitch somewhere in the middle of two official releases.
> 
> The situation is different for test releases, because they are *almost* the next release, so any efforts to port towards them are not lost.