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

From: jerzy.karczmarczuk at info.unicaen.fr (jerzy.karczmarczuk at info.unicaen.fr)
Date: Mon Jan 28 14:16:01 EST 2008

Noel Welsh: 

> Benjamin L. Russell <dekudekuplex at yahoo.com> wrote:
>> 2) Recently, there seems to have been a great increase
>> in focus on lazy evaluation across the functional
>> programming landscape.  How well, and in what manner,
>> does Scheme, as a language with strict evaluation,
>> cope with this trend?
> What you may be seeing here is the dominance of Haskell in the
> functional programming community (certainly Haskellers were the most
> prevalent group at this year's ICFP).  

etc. etc. Then the discussion diverged towards types, Haskellisms, and
other issues not so strongly related to the original posting. 

People, why nobody dared to mention the Lazy Scheme module. Eli? 

Of course, laziness goes with the purity, but it is unrelated to strong

Carl Eastlund writes: 

> Pure just means it's missing some stuff.  ;)

Well if somebody says to a surgeon enetering the operation room:
"wouldn't be better if you go first and have those mmm.... things missing
from your hands, mask and blouse, before you touch the patient", then
issuing a wink_smiley with it might be not really appropriate. 


For me laziness is an algorithmization tool. It permits to transform
equations into effective codes (perhaps not always terribly efficient,
but this is another story). With the call-by need you can implement
relatively fast some co-recursive routines, coding in a way which omits
plenty of administrative stuff (termination conditions).
I believe that scientific community will learn how to use it more intensely,
and I think that the person who said that the interest in lazines is
dwindling, is wrong (unless it is somebody who always knew and knows

Jerzy Karczmarczuk 

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