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];
Objective-C objects are reference counted; to ensure that they are retained and
released at the proper times, we can use the Id struct.
To enforce aliasing rules, an Id can be either owned or shared; if it is
owned, meaning the Id is the only reference to the object, it can be mutably
dereferenced. An owned Id can be downgraded to a ShareId
which can be cloned to allow multiple references.
Weak references may be created using the WeakId struct.
``` rust let cls = Class::get("NSObject").unwrap(); let obj: Id
// share the object so we can clone it let obj = obj.share(); let anotherref = obj.clone(); // dropping our other reference will decrement the retain count drop(anotherref);
let weak = WeakId::new(&obj); assert!(weak.load().issome()); // After the object is deallocated, our weak pointer returns none drop(obj); assert!(weak.load().isnone()); ```
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(); ```