[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

addendum about informality and tail recursion

   Date: Tue, 03 Jun 1997 16:52:49 -0500
   From: William D Clinger <will@ccs.neu.edu>

   That's what I would assume, because the term was invented
   to describe an implementation.  What does it mean to you,
   if not an implementation strategy?

It means a conceptual abstraction in which there are two useful
"directions" of motion... down and up.  One can "push" (down) to a new
context, and one can "pop" (up) to stop doing what one is doing now
and return to whatever needs to be done next.  The fact that the
"stack" might not be linear, and might indeed contain cycles if the
power of full continations is used, is of no relevance to the
abstraction level I'm referring to, since the whole point is to keep
such a localized view of the world that you never have any sense for
what the global flow is and whether you're repeating yourself.

That doesn't sound like an "implementation description" to me.
Your mileage may vary.