Thu, 13 May 1999 13:50:45 -0700 (PDT)
> I'm confused about the last paragraph. I agree that it is surprising that
> you can eliminate tuples entirely once you go to N-ary functions and
> constructors, but it seems that to avoid blow up (in the sense of unbounded
> extra allocation) you need to know that dynamically you don't use it in
> such things. Not statically.
Yes. But the static count ensures that the data flow of a tuple never
"splits" into two different paths, which is enough to guarantee the
> Also, you inc the count on selects? This would seem to break
> fun z =
> let val x = #1 z # first use of z
> val y = #2 z # z is now MANY
> Have I missed something?
Oops. I misread the code. In looking more closely, it carefully
avoids incrementing the count for Select expressions. The count is
only incremented for Tuple, Known, Con, and Prim.