This was brought up in the thread reviewing std.serialization:
http://forum.dlang.org/thread/adyanbsdsxsfdpvoo...@forum.dlang.org
Currently we haven't started to use UDA's in Phobos or druntime yet (as
far as I know). I would like to start a discussion about putting out
some guidelines for using UDA's in Phobos/druntime.
I've created a small module that handles UDA's:
https://github.com/jacob-carlborg/orange/blob/master/orange/core/Attribute.d
The idea is to have a kind of meta UDA called "attribute". This
attribute needs to be attached to all structs, enums and so on that is
to be used as an attribute.
The module provides a template (getAttributes) to get, by default, only
those values attached to a given symbol that is an attribute. That is,
marked with the "attribute" attribute.
So my suggestion for guidelines are:
* Only types with the "attribute" UDA is to be used as attributes
* In general, don't use primitive values as a UDA
Don't use this
@(3) int a;
Use this:
@attribute struct foo { int b; }
@foo(3) int a;
* A user defined type marked with "attribute" should not be used for
something else than an UDA
* All attributes use camel case names
If we agree on this and that we need a module like the one above I think
it should be added to druntime. The reason for that is that we most
likely want to use UDA's in druntime and not only in Phobos. Example, if
we ever get std.serialization into Phobos we would want to mark Thread
and similar structs/classes as "nonSerialized".
Thoughts?
--
/Jacob Carlborg
