Fun with lambda and map
ivo at nospamAmaze.nl
ivo at nospamAmaze.nl
Mon Feb 4 11:38:07 EST 2002
Jason Orendorff <jason at jorendorff.com> wrote:
: Ivo wrote:
:> I implemented some of the pure (?) lambda calculus in python:
:> http://vanderwijk.info/lambda
:> Who needs '+' , 'if' and numbers? :)
: Wow. It's extra cool that this should come up, because I just
: recently tore through the first chapter of SICP, and wrote this:
: http://www.jorendorff.com/toys/truth.html
I extended the calculus a bit with mul (based on your sig :) and pred,
hoping that I could fac in lambda, but I guess I've reached pythons lambda
limits.
The statement:
fac = lambda q: if_then_else(is_zero(pred(q)))(n1)(mul(q, fac(pred(q))))
(check vanderwijk.info/lambda for the other definitions)
will recurse endlessly, because the else-part will always be evaluated
(but just not used as a result).
(why I do all this? Just pure academic interest - lambda calculus
used to fascinate me at the university)
Ivo
--
Drs. I.R. van der Wijk -=-
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