Re: breadcrumbs for Info . . . . . .

[Juri Linkov]

>    Even if the "cache" consisted only of a set of node+parent pairs
>    (regardless of the order among pairs), that would be sufficient.
>
> A slight twist on that data structure will give us a "reverse trie",
> which is a set of elements (NODE PARENT PARENT^2...), with elements'
> tails sharing storage (i.e, being other elements of the set).

This is too complex structure for shallow short trees of Info manuals.
Now the cache has the structure (NODE PARENT CHILDREN) that allows
optimal navigating the tree in both directions: bottom-up to build the
breadcrumbs, and top-down to build the TOC node.

-- 
Juri Linkov
http://www.jurta.org/emacs/