This change allows a
#[namespace (namespace = A::B)]
attribute for each item in a cxx::bridge.
We now have a fair number of different types of name floating
around:
* C++ identifiers
* C++ fully-qualified names
* Rust identifiers
* Rust fully-qualified names (future, when we support sub-modules)
* Items with both a Rust and C++ name (a 'Pair')
* Types with only a known Rust name, which can be resolved to a
C++ name.
This change attempts to put some sensible names for all these
things in syntax/mod.rs, and so that would be a good place to start
review.
At the moment, the Namespace (included in each CppName)
is ruthlessly cloned all over the place. As a given namespace is
likely to be applicable to many types and functions, it may
save significant memory in future to use Rc<> here. But let's not
optimise too early.
This adds support for passing C-style enums between Rust and C++.
We use the Rust representation for enums suggested by dtolnay in #132.
Note that as this does not use real enums, Rust code cannot treat them
as normal enums, e.g., by converting them to integers. But common
uses such as pattern matching remain unchanged.
