Subj : Re: Compiler and an interpreter
To   : comp.programming
From : Jon Harrop
Date : Sun Aug 07 2005 11:36 pm

Arthur J. O'Dwyer wrote:
>> I don't understand the last line, so I may have solved a different
>> problem!
> 
>    I don't know for sure, but I strongly suspect
>      nth(i, n) = union(j in nth(i,n-1), nth(i, 1)) - ...
> was supposed to read
>      nth(i, n) = union(j in nth(i,n-1), nth(j, 1)) - ...
>
> Otherwise, what's the point of mentioning 'j'?

Oops, yes.

>    Once that change is made, I think it's easy to read the expression as
> calculating, as you said,
>> nth( i, n ) = all neighbours of nth( i, n-1 ), that don't appear in
>> nth( i, n-1 ) or nth( i, n-2 )

Yes.

-- 
Dr Jon D Harrop, Flying Frog Consultancy
http://www.ffconsultancy.com

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