[plt-scheme] [ANN] Heist: a Scheme interpreter in Ruby

From: Shriram Krishnamurthi (sk at cs.brown.edu)
Date: Fri Jul 31 23:22:15 EDT 2009

On Wed, Feb 25, 2009 at 2:23 PM, Raoul Duke<raould at gmail.com> wrote:
> hi,
>> Finally, though for a long time I used to think of event-driven
>> programs as being "merely CPS", I have now come to see them as
>> something different -- as what (for lack of a better name) I call
>> "event-style".  It's not quite the same thing at all.
> i am curious to learn more. (i'm a bit surprised to hear of someone
> seeing them as nigh same. perhaps that's something to do with me doing
> more C/++/#/Java coding than Scheme.) might you describe the salient
> differences you have in mind?

I keep meaning to get around to responding to this at length and never
do.  So I'll keep it short.

CPS is merely a transformation technique.  It can be applied to any
kind of program.  It can certainly be applied to a direct-style
program to create entry points that an event-driven program needs.
But it can be used for other things, too.

Event-driven programs have no "main".  They are ONLY a collection of
callbacks.  There is no canonical control flow through such a program;
rather, there are innumerable control flows, all in the hands of the
event handler and, ultimately, the external stimuli (user, etc).

That's the high-order bit.


Posted on the users mailing list.