Objective-C Runtime bindings and wrapper for Rust.
Objective-C objects can be messaged using the msg_send! macro:
rust
let cls = Class::get("NSObject").unwrap();
let obj: *mut Object = msg_send![cls, new];
let hash: usize = msg_send![obj, hash];
let is_kind: BOOL = msg_send![obj, isKindOfClass:cls];
// Even void methods must have their return type annotated
let _: () = msg_send![obj, release];
Classes can be declared using the ClassDecl struct. Instance variables and
methods can then be added before the class is ultimately registered.
The following example demonstrates declaring a class named MyNumber that has
one ivar, a u32 named _number and a number method that returns it:
``` rust let superclass = Class::get("NSObject").unwrap(); let mut decl = ClassDecl::new(superclass, "MyNumber").unwrap();
// Add an instance variable
decl.addivar::
// Add an ObjC method for getting the number extern fn mynumberget(this: &Object, cmd: Sel) -> u32 { unsafe { *this.getivar("number") } } unsafe { decl.addmethod(sel!(number), mynumberget as extern fn(&Object, Sel) -> u32); }
decl.register(); ```
By default, if the msg_send! macro causes an exception to be thrown, this
will unwind into Rust resulting in unsafe, undefined behavior.
However, this crate has an "exception" feature which, when enabled, wraps
each msg_send! in a @try/@catch and panics if an exception is caught,
preventing Objective-C from unwinding into Rust.