[m-dev.] Hm, yes, re: obsolete bintree(_set)

[doug.auclair at logicaltypes.com]

Dear Julien,

>For the benefit of all of involved in this discussion I draw your attention to
>the following comment at the top of bintree.m:
>        % Stability: medium (obsolete).
>        %
>        % This module exists primarily for historical reasons. It is unlikely
>        % to be useful, and may not be supported in future releases.
>        % You should use `map' instead.
>Similarly for bintree_set.m.  AFAIK this is still the case and while it is
>we won't be adding anything to these modules.

Yes, but 1. it /is/ useful for those of us user who wish to use a balance binary (not N-ary) tree (so, from a practical standpoint, the comment is wrong) and 2. I've seen this message since circa 0.10.1 or so?  This makes it hard for me to give the obsolete marking in the comment block (not, as you see, as any pragma to any item in the modules' protocols) any credit ... And bintree(_set) is still in the ROTD, meaning, given the release lag, that it will be with us for AT LEAST another year.  Perhaps, then, it should be a productive (AT LEAST) year?  That was the thrust of my posts: if I need to do other than left-to-right traversal of the set, perhaps other users needed the same functionality.

Or, perhaps these modules should be removed immediately from the ROTD and next release, preventing pesky gadflies, such as myself, from raising  feasible usage issues with published protocols?  This same comment applies to the (more than one) modules that state at their head "this module is exactly the same as module X, use that module instead".

Of course, removing bintree(_set) means that anyone needing to use an AVL tree would be required to implement this code, for themselves, each time a need occurred.
-----
Fresh, but related, topic.  I've seen the work on the benefits of AVL trees and various implementations of that data-type and protocol, but the Mercury group is predisposed to use 234 trees.  Is there some literature by which I may educate myself that shows clear benefits of 234 trees over AVL trees?

Sincerely,
Doug Auclair

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