std/objc

Objective-C on macOS, through the C functions of its runtime, so it needs no Objective-C compiler; a module that uses it is marked #![unsafe]. On other systems the module is empty.

#![unsafe]
import "std/objc"

Handle text = ns_string("hola")
print(msg_int(text, "length"))                    // 4
c_func(Handle, Handle, Handle) Handle append = ptr_cast(msg_send())
Handle both = append(text, selector("stringByAppendingString:"), ns_string("!"))
print(from_ns_string(both))                       // hola!

A message is sent through objc_msgSend as a c_func of the method's signature, with the receiver and the selector first; msg_send() gives it.

Function	Result
`objc_class(name)`, `selector(name)`, `class_name(object)`	a class, a selector, and the name of an object's class
`msg(o, name)`, `msg_with(o, name, a)`, `msg_with2(o, name, a, b)`	a message that gives an object
`msg_int(o, name)`, `msg_at(o, name, index)`	a message that gives an integer, and one that takes one
`new_object(class)`	`[[class alloc] init]`
`with_autorelease_pool(body)`	runs `body` in an autorelease pool
`ns_string(text)`, `from_ns_string(s)`	NSString
`ns_array(items)`, `from_ns_array(a)`	NSArray of objects
`ns_dictionary(entries)`, `from_ns_dictionary(d)`	NSDictionary with text keys
`ns_data(data)`, `from_ns_data(d)`	NSData
`ns_url(address)`, `ns_url(path, file: true)`, `from_ns_url(u)`	NSURL
`start_class(name, superclass)`, `add_method(class, name, implementation, types)`, `finish_class(class)`	a class written in Cuarzo, such as a delegate
`set_object_data(class, object, handle)`, `object_data(class, object)`	the data of Cuarzo each object of such a class holds
`make_block(invoke, handle)`, `block_data(block)`, `free_block(block)`	a block whose code is a Cuarzo callback

A method's implementation and a block's code are C functions from c_callback: a method takes the object and the selector first, and its types are its Objective-C type encoding, as "v@:" or "q@:q"; a block's code takes the block first, whose data block_data gives.