[isabelle-dev] »real« considered harmful

Dmitriy Traytel traytel at in.tum.de
Wed Jun 24 16:13:39 CEST 2015


You can hover in the output panel, but you won't see types of constants 
there.

Dmitriy

On 24.06.2015 16:09, Manuel Eberl wrote:
> Ah, I see the problem. In that case, one could still hover over the 
> "of_nat" in the output window, but it is perhaps not ideal.
>
>
> On 24/06/15 16:08, Dmitriy Traytel wrote:
>> I guess what Larry means is there is no way to see a type of a 
>> constant that is not there in the source.
>>
>> Consider e.g.
>>
>> declare [[coercion "of_nat :: nat ⇒ real"]]
>> term "sqrt (2 :: nat)"
>>
>> Today the output says "sqrt (real_of_nat 2)". But if there would be 
>> no abbreviation for "of_nat :: nat ⇒ real", how would you deduce the 
>> type of the coercion.
>>
>> Dmitriy
>>
>> On 24.06.2015 16:01, Manuel Eberl wrote:
>>> On 24/06/15 15:55, Larry Paulson wrote:
>>>> A more appropriate point is that it can be tricky in Isabelle/jEdit 
>>>> to determine the type of an expression such as “of_nat k”, as there 
>>>> is nothing to click on.
>>> When I type ‘term "sqrt (of_nat 2)"’ and hover over the ‘of_nat’, it 
>>> says ‘constant "Nat.semiring_1_class.of_nat" :: nat ⇒ real’.
>>>
>>>
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>>> isabelle-dev mailing list
>>> isabelle-dev at in.tum.de
>>> https://mailmanbroy.informatik.tu-muenchen.de/mailman/listinfo/isabelle-dev 
>>>
>>
>




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