Prolog-style unification?

[Nielson Family]

Ype,

See comments  inline:

Ype Kingma wrote:

>>Calling Father this way could make it difficult to use it
>>in multiple places in a single clause. An iterator per occurence
>>seems just right, although I have to say that it
>>is decades ago that I used Prolog...
>>
I'm not sure what you mean by this.  Could you elaborate?

>>
>>Some questions:
>>Is logic.Fact the good class for the backtracking needed?
>>
The short answer is 'yes', the long answer is 'its complicated'.  I'll 
post code in a week or two and you can see what's going on for yourself.

>>Do you use 'yield' for backtracking?
>>
No.  But maybe I should.  I'm still working out the most efficient way 
to do backtracking.  If you know any very efficient backtracking 
algorithms, please let me know.

Thank you for your feedback,

-- Seth