Hi there,

if you look about a quarter of the way down this page ( the introductory tutorial) http://www.macruby.org/documentation/tutorial.html

you will see it all explained.

In this case:

- (BOOL)windowShouldZoom:(NSWindow *)window toFrame:(NSRect)proposedFrame

could become:

windowShouldZoom(window,  toFrame:proposedFrame)

there are other ways too, check out the page above.

Cheers,

J