objc:define-objc-struct

(objc:define-objc-struct (name (:foreign-name "Name") [(:typedef-name alias)]) (slot-name slot-type)*)

Defines the structure type name, usable as (:struct name) (and alias) in objc:invoke's list form and in the defining macros. :foreign-name is the name the runtime's encodings use. A value of it is a vector of its fields in memory order, as objc:invoke passes and answers any structure other than the four cocoa ones. Part of the macOS-only objc package -- the interpreter (java -jar, or the rontolisp native binary), a compiled .class / .jar and a --native executable for macOS on Apple silicon, never a .wasm. The definition needs no runtime: the Objective-C side is made when the runtime is opened (objc:ensure-objc-initialized, or the first send). See the macOS GUI guide.

MY-APP> (define-objc-struct (pair (:foreign-name "_Pair"))
          (:first :float)
          (:second :float))
PAIR
MY-APP> (define-objc-method ("pair" (:struct pair)) ((this my-object))
          (vector 1.0 2.0))
"pair"
MY-APP> (invoke (alloc-init-object "MyObject") "pair")
#(1.0 2.0)