[plt-scheme] call-by-value vs. call-by-name?

From: Benjamin L. Russell (dekudekuplex at yahoo.com)
Date: Wed Jan 30 22:13:24 EST 2008

Which paper from FPCA 1995
are you referring to?  Is it the one from Session 7,
by Klaus E. Schauser and Seth Copen Goldstein,
entitled "How Much Non-Strictness do Lenient Programs

I haven't read the relevant paper yet, so I would need
to read it first to be sure, but it would seem to be
the case that if a function had a statement that,
under call-by-value, would require evaluating multiple
arguments, and, under call-by-need, would require
evaluating only a single argument, the call-by-need
version could run faster.

Is there some other reason that it is not true that
everything ought to be lazy?

Benjamin L. Russell

--- Matthias Felleisen <matthias at ccs.neu.edu> wrote:

> On Jan 28, 2008, at 2:08 PM, Shu-yu Guo wrote:
> [snip]
> Once again, the idea that everything ought to be
> lazy has been  
> debunked, see FPCA 1995. The quick summary is that
> if you look at any  
> large code basis you realize that you definitely do
> want lazy  
> constructors but lazy functions is an entirely
> different thing. As  
> far as I can tell, people who are willing to look at
> this from a  
> reasonably neutral effort have come to agree that
> the examples that  
> demonstrate the need for lazy functions are toy
> examples.
> [snip]

Posted on the users mailing list.