So, like, the other day David Gibson mumbled:
quoted
The doubly-linked list is intended to make it easier to construct search
path lists one-at-a-time from arguments in the proper order, without
needing to reverse the list at the end.
We've already got that problem with a bunch of the lists we create
during parsing (we have several ugly add-to-end-of-singly-linked-list
functions). Going to doubly-linked lists might not be a bad idea, but
we should do it across the board, probably using the kernel's list.h
or something like it.
I would be happy to accept a kernel's-list.h-based refactoring
for doubly linked lists after the imminent 1.1 release!
jdl