There is something I'd like to mention, not a big deal, but worth considering.

I've been doing some proofs lately after a long gap, making myself a 
combination of a novice and expert. And I've got confused by things that would 
probably confuse true novices even more.

Here are two instantiations, both of which simply do overloading but justify no 
properties. Such instantiations always succeed, because there is nothing to 
prove. But I discovered that you have to be very careful to introduce 
overloading correctly. If it's wrong, the instantiation effectively does 
nothing; when that happens, a warning ought to appear.

The overloading rules are quite tricky. I don't understand why the first 
instantiation requires a definition of sup_hf (including the type in the 
constant name), while the second one simply requires a definition of minus. 
Perhaps because there is an explicit type in the first instantiation and not on 
the second one? In any event, if the user gets wrong, a warning would be 
appropriate. And I hope that wouldn't be difficult to implement.

instantiation hf :: sup
begin

definition sup_hf :: "hf \<Rightarrow> hf \<Rightarrow> hf"
  where "sup_hf a b = ..."

instantiation hf :: minus
begin
definition minus_hf where
  "minus A B = ...
instance proof 


Larry

On 12 Apr 2012, at 10:02, Makarius wrote:

> Dear all,
> 
> we need to get to a more concrete release schedule.  Presently I would like 
> to aim for late May, which means we need to start consolidating and 
> converging about now.
> 
> Are there any further big things in the pipeline?
> 
> This is also a good point to populate NEWS, CONTRIBUTORS, and update manuals 
> to cover new things.  (I am speaking to myself here as well.)
> 
> 
>       Makarius
> _______________________________________________
> isabelle-dev mailing list
> [email protected]
> https://mailmanbroy.informatik.tu-muenchen.de/mailman/listinfo/isabelle-dev

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