User attributes (was Proposal on improvement to deprecated)

[bearophile]

Piotr Szturmaj:

> for user defined attributes (I need to write DIP on that).

Please write that DIP :-) Even if it will be refused, it will be a starting point to build on successive better ideas for user defined attributes.


> There are of course many other possible use cases like Object/Relational
> Mapping, RPC/Remoting, debugger visualization overrides, hints for the
> GC, etc.

I see user defined attributes also as ways to extend the type system with in library/user code, a bit like dehydra/treehydra (but with no need to use another language to specify them). But I think more static introspection will be needed for that. I mean things like a __trait that given a function name, returns an array of the names of all its local variables, a __trait that tells if a variable used in a function is locally defined, globally defined, if it is static, etc. Some of such info is already present in the JSON documentation about modules. So a way to perform searches on such JSON at compile time will be useful. Eventually maybe even linear types or uniqueness types become implementable with annotations.

Bye,
bearophile