DIP6: Attributes

[Don]

grauzone wrote:
> Don wrote:
>> Ary Borenszweig wrote:
>>> http://www.prowiki.org/wiki4d/wiki.cgi?LanguageDevel/DIPs/DIP6
>>
>> This looks like a solution in search of a problem. What's the problem 
>> being solved?
> 
> Attaching additional data to types, that can't be specified otherwhere. 
> This should help with metaprogramming-like stuff.
> 
> For example serialization. How do you specify that a field shouldn't be 
> part of the serialized data? Java has an extra keyword attribute like
> "transient" (comes from before attributes were introduced). C# uses what 
> we call annotation in this thread. How would you do this in D?

I agree that there doesn't seem to be a nice way at present. One 
possibility would be to establish a naming convention for transient 
fields -- a Ruby-style solution, I guess.

But are annotations actually an ideal solution for this problem?
Presumably, you'll have to specify that somewhere else anyway. I mean, 
during reading it will need to either be initialized separately after 
serialisation (like opPostBlit, perhaps?), or else remain uninitialized. 
Serialisation seems to be _extremely_ similar to construction. I'm not 
sure that annotations capture that.

D has much more powerful metaprogramming than C# or Java, so my 
intuition and hope is that we shouldn't need to adopt hacks from those 
weaker languages. The annotation syntax in C# and Java looks like an 
ugly hack to me. Purely a subjective opinion, of course, but it seems 
really out of place in a C-family language.