[fpc-pascal] Case statement for class introspection

Marco van de Voort fpc at pascalprogramming.org
Sun Jan 16 14:38:51 CET 2022

On 16-1-2022 14:18, Ryan Joseph via fpc-pascal wrote:
> I had some fun today on my day off and managed to actually implement this based on the if-statement based string case labels. Is the compiler team interested in this feature? I think it's a clearly useful addition to OOP and an appropriate new use of the case statement.
> https://gitlab.com/genericptr/free-pascal/-/commits/case_label_classref
> Here's an example of what I did. To keep it simple you use "ClassType" to branch off of possible class types.
> ========================
>    o := TInterfacedObject.Create;
>    case o.ClassType of
>      TObject: writeln('TObject');
>      TInterfacedObject: writeln('TInterfacedObject');
>      TAggregatedObject: writeln('TAggregatedObject');
>      otherwise
>        writeln('OTHER: ',o.ClassName);
>    end;

What does it print in this case? I mean tobject matches, and 
tinterfacedobject too.

The most logic solution would be to only run the most specialized case?

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