[Haskell-cafe] Comparison with Clean?

karczma at info.unicaen.fr karczma at info.unicaen.fr
Wed May 4 17:24:56 EDT 2005

Benjamin Franksen writes: 

> karczma at info.unicaen.fr wrote:
>> Bryce Bockman writes:

>> Don't confuse categories please. SICP doesn't say how to make a lazy
>> variant of Scheme. Applicative protocol is not normal protocol, the
>> reduction is, as it is. 
> We may have a different copy of SICP, but in mine (2nd edition) there is 
> Chapter 4.2 "Variantions on a Scheme -- Lazy Evaluation" and in particular 
> 4.2.2 "An Interpreter with Lazy Evaluation".

Absolutely right, and BTW., I had
on the screen when I wrote what I wrote. Michael Vanier explained well
my aim (better than myself, an optional sad smiley here...). 

I wanted just to say that a lazy interpreter etc., *is not Scheme*. Well,
AS say: "In this section we will implement a normal-order language that is
the same as Scheme except that compound procedures are non-strict in each
argument. Primitive procedures will still be strict." We read, and we see
that the lazy layer is a superficial one, with 'forcing' implemented at
the surface, so for me it was enough to remark that I consider it to be
a different language. 

Sorry for the hair-splitting manners, I didn't want to annoy anybody. 


On the other hand, it would be an interesting pedagogical initiative to
take such language as Scheme, but instead of making a "Scheme variant",
"metacircular" etc. in it, to try to implement a genuine lazy graph
reduction strategy, as in Clean. Or implement a kind of STG Haskell


Jerzy Karczmarczuk 

More information about the Haskell-Cafe mailing list