objc:invoke

(objc:invoke class-or-object-pointer method &rest args)

Sends a message and answers its value. The receiver is an object pointer, a class pointer, or a string naming a class (a class method); nil answers nil. method is the selector with its colons ("setWidth:height:"), or a list (name arg-types &key result-type variadic-num-of-fixed) that states the types itself -- the form a variadic method needs. Arguments and the result are converted by the method's declared types: a string or a vector passes as an NSString / NSArray released when the call returns, #(x y width height) as an NSRect, (location . length) as an NSRange, t / nil as a BOOL, a foreign object (fli) as a pointer or, copied, a structure; a BOOL result is 1 or 0, an NSRect a vector, an NSRange a cons, an object an objc:objc-object-pointer and a pointer a foreign pointer. A method the receiver does not have signals No method ... for object ... before anything is sent. 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; on a machine without the runtime it signals an error. See the macOS GUI guide.

CL-USER> (defvar *s* (objc:invoke "NSString" "stringWithUTF8String:" "hello world"))
*S*
CL-USER> (objc:invoke *s* "length")
11
CL-USER> (objc:invoke *s* "rangeOfString:" "world")
(6 . 5)
CL-USER> (objc:invoke (objc:invoke "NSScrollView" "alloc") "initWithFrame:" #(0 0 100 100))
#<Pointer: OBJC:OBJC-OBJECT-POINTER = #x0000600003B04000>