objc:invoke-into

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

objc:invoke whose answer is converted or stored as result says. The symbol string converts an NSString result to a Lisp string; array converts an NSArray to a vector of pointers, and (array string) (nesting allowed) converts its elements too. A vector is filled with an NSArray's elements, or with an NSRect / NSSize / NSPoint result's fields; a cons receives an NSRange result's location and length, and a foreign object (fli) receives any result of its type. :pointer answers a C-string result as its address. Any other combination answers what objc:invoke would. 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> (objc:invoke-into 'string *s* "description")
"hello world"
CL-USER> (let ((rect (make-array 4)))
           (objc:invoke-into rect (objc:invoke "NSValue" "valueWithRect:" #(1 2 3 4)) "rectValue")
           rect)
#(1.0 2.0 3.0 4.0)
CL-USER> (objc:invoke-into '(array string) (objc:invoke "NSArray" "arrayWithArray:" #("a" "b")) "self")
#("a" "b")