Or follow Alef (http://www.cs.bell-labs.com/who/rsc/thread/ug.pdf http://www.cs.bell-labs.com/who/rsc/thread/ug.pdf) and use "become". The Alef become statement

Or follow Alef (http://www.cs.bell-labs.com/who/rsc/thread/ug.pdf http://www.cs.bell-labs.com/who/rsc/thread/ug.pdf) and use "become". The Alef become statement is a kind of generalized tail-call form because you can use it to drop the current stack frame from anywhere, not just in tail-position.