No, that's probably wrong. With MacRuby, bridging is toll-free, and, as others have noted already, there is a much lower impedance mismatch between ruby and objective c than there was between java and objective c. Apple has improved the support for scripting languages over the years with the introduction of the scriptingbridge framework. These days, you can easily write an app on the mac in either ruby or python, the only constraint is that things become a mess if ever raw c structs are exposed by the cocoa api (and yes, there are still a few places where this is the case), or worse still when there is no cocoa api for a particular framework. Still, even in these cases there us some support in the scripting bridge framework, although my personal preference for this type of problem is just to wrap the c code in an objective c wrapper class before using the wrapper class from within MacRuby. Works like a charm!