Implement Index<Range>, Index<RangeFrom>, Index<RangeTo>, Index<RangeFull>

[Geal]

Hi!

People are asking for bit level parsing in nom, and to use BitVec, I would need to implement those traits to get the slicing syntax on bit streams.

I see in the code that Index<usize> is already implemented, but there's a big warning. Could you explain what it means?

I can try to implement those, but I wonder if you would accept it (because of that warning)

[Gankra]

Ah, hehe. The NOPE NOPE NOPE is me being upset that we need to "hack" around the Index trait's design by outputting references to TRUE or FALSE statics. It's workable; just stupid.

[Gankra]

That said, I don't think you can use indexing for bit-ranges. You can't return an &[u1], you'll have to return an iterator.

[Geal]

yes, it makes sense. Since nom uses a lot of macros, I just need to trick it into thinking it is a real slice. Maybe by returning a Vec<bool> generated from the specified range?

[Geal]

I'm not sure adding it to this crate would be worth the trouble if it is only used in nom. But then, my only option is to duplicate the code, since I can't implement the traits on BitVec from another crate :(

[Gankra]

How would you return a Vec<bool>? Indexing requires that you return a reference.

(hence the desire for IndexGet)