Tue Aug 23 16:46:47 CEST 2011

Code gen & let/if

It's not only sharing, it's also conditionals that can make code
generation through abstract evaluation a bit problematic.  Note that a
"strict" if is not a problem, as long as both legs are computed the
code can be generated, and the dispatch only selects a value.  The
problem is with "lazy" if.