Re: functional programming is great, but why lists?

[Michael Vanier <mvanier@bbb.caltech.edu>]

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> Date: Thu, 11 Oct 2001 20:10:58 -0500
> From: Bill Richter <richter@math.nwu.edu>
> Cc: plt-scheme@fast.cs.utah.edu
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> 
>    In Olin Shivers' memorable phrase,
>    
>      Minimalism and elegance will guide design, but we should bear in
>      mind the dictum that "things should be made as simple as
>      possible, but no simpler." Lambda is not a universally sufficient
>      value constructor.
>    
> Sounds good, Shriram.   Would (I almost said "could" :)) you explain
> why it's not, why we need lists too?
> 
> 

Of course, if you have lambda you _already_ have lists.  Here's an example
from SICP (apologies to those who've seen this before):

  (define (cons x y)
    (lambda (m) (m x y)))

  (define (car z)
    (z (lambda (p q) p)))

  (define (cdr z)
    (z (lambda (p q) q)))

Thus, I don't understand Olin's comment about lambda not being sufficient,
unless lambda + lists are also not sufficient.  I'm not being facetious; I
know this is hopelessly inefficient, but we're talking about what's
necessary in principle.

Mike