There are four commonly used structure types in Cocoa that have equivalents in the Objective-C interface. In addition, each one has a helper function that will set its slots.
Objective-C type
FLI type descriptor
Helper function to set the slots
NSRect
ns-rect
set-ns-rect*
NSPoint
ns-point
set-ns-point*
NSSize
ns-size
set-ns-size*
NSRange
ns-range
set-ns-range*