Re: possible strange idea about hierarchical lists

[prj@po.cwru.edu (Paul Jarc)]

Ted Zlatanov <tzz@northernlight.com> wrote:
> Parsing of the hierarchy specification.  It's a tree structure, with
> the widest-coverage lists at the top and more specific lists at the
> bottom.  I suppose it could be hacked as a 2-level list, but a tree
> hierarchy is more generic.

The 2-level list is just as expressive, I think, and easier to
implement.  Suppose A contains B, and B contains C, and you have a
message addressed to B and C.  In order to strip out C, you'd have to
traverse the entire tree to first find B; there's no guarantee that
the top level will have anything interesting.

Also suppose A nd D both contain B.  This is actually easier to
express with the 2-level list; with a tree, you'd have to duplicate
the whole subtree under B.  With a 2-level list, you just add B under
both A and D, and the code takes care of looking for a top-level B
with its own entries under it.


paul