Re: Zoo question

[dewar@cs.nyu.edu (Robert Dewar)]

Ted Dennison says, referring to the Zoo example

"...or the check could be placed around the next USE of the value. This could
well be a useful optmization in some circumstances."

This transformation is only allowed if it is semantically invisible, and
hence does not need to enter into a discussion of the semantics of the Zoo
program. note in particular that such a transformation is not permitted
if it changes any external effect, or if it moves a CE outside the
current frame.