From: Tim Hunter <TimHunter@...>
Date: 2007-11-12T10:46:20+09:00
Subject: Re: The Man or Boy Recursion Test

Morton Goldberg wrote:
> On Nov 11, 2007, at 6:42 PM, Tim Hunter wrote:
> 
>> Ummmm...before I wrote C I wrote PL/I. Not a lot, but enough to be 
>> able to use the PL/I version of the Man or Boy test to figure out how 
>> to code the Ruby version.
> 
> Interesting. I used your Ruby version to figure out how to code it in 
> Mathematica. I was able to make a fairly direct translation.
> 
> <code>
> $RecursionLimit = 1665; (* anything less fails for k0 = 10 *)
> 
> a[k0_, x1_, x2_, x3_, x4_, x5_] := Module[{k, b },
>   k = k0;
>   b = (k--; a[k, b, x1, x2, x3, x4]) &;
>   If[k <= 0, x4[] + x5[], b[]]]
> 
> a[10, 1 &, -1 &, -1 &, 1 &, 0 &] (* => -67 *)
> </code>
> 
> Note how compact the Mathematica notation for the thunks is.
> 
> Regards, Morton
> 

Another one for Wikipedia. I guess we owe Werner (the OP) a big "thanks" 
for introducing such an interesting thread. Thanks, Werner!

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