Make getAttr, getSpecificAttr, hasAttr, and hasSpecificAttr variadic #78518
Conversation
Discussed elsewhere, it makes sense to have these functions be variadic. They work as an 'or', that is, 'has*Attr' is "one of the set", and "get*Attr" means "first of the set". This is accomplished by extracting specific_attr_iterator into a _impl version, and creating a version + partial specialization for the _iterator version that inherits from the _impl. The result is that all of the 'existing' code 'just works'. One exception (see the change in SemaOverload.cpp) could be solved with a conversion function, but instead I put 'auto' in. Else, I could specify the 'AttrVec' if it were preferential.
There was a problem hiding this comment.
Created as a draft, but I'd still love feedback on the approach, see if there is anyone with ideas on how to manage the 'might take just a single attr, might take a container + variadic list' functionality (as combining a default and a variadic parameter isn't really possible afaik).
I haven't found a good use for the variadic functions yet, but can either look more, or take suggestions/will put them in as a part of moving this to not a draft.
| }; | ||
|
|
||
| template <typename Container, typename... SpecificAttrs> | ||
| class specific_attr_iterator |
There was a problem hiding this comment.
I have a version I played with where I put a conversion operator here, so that we can convert to the partial specialization, but it would only be useful in 1 place.
The downside we have here is you cannot do:
specific_attr_iterator<MyAttr> Foo = Decl->specific_attr_iterator_begin<MyAttr>()
since the two specializations are 'different' types. I was hoping @ldionne /someone else might have a clever way of combining the uses of these two.
| NewE = New->specific_attr_end<EnableIfAttr>(), | ||
| OldI = Old->specific_attr_begin<EnableIfAttr>(), | ||
| OldE = Old->specific_attr_end<EnableIfAttr>(); | ||
| for (auto NewI = New->specific_attr_begin<EnableIfAttr>(), |
There was a problem hiding this comment.
A conversion operator makes this unnecessary, but it is only used 1x, so I wasn't sure of its value.
Discussed elsewhere, it makes sense to have these functions be variadic. They work as an 'or', that is, 'hasAttr' is "one of the set", and "getAttr" means "first of the set".
This is accomplished by extracting specific_attr_iterator into a _impl version, and creating a version + partial specialization for the _iterator version that inherits from the _impl. The result is that all of the 'existing' code 'just works'.
One exception (see the change in SemaOverload.cpp) could be solved with a conversion function, but instead I put 'auto' in. Else, I could specify the 'AttrVec' if it were preferential.