[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: lexicographic list comparison
From: |
Mattias Engdegård |
Subject: |
Re: lexicographic list comparison |
Date: |
Sat, 10 Sep 2022 11:07:49 +0200 |
9 sep. 2022 kl. 21.27 skrev Sam Steingold <sds@gnu.org>:
> What do you do when sorting a list of lists of numbers?
Sigh deeply and write ad-hoc code for the nth time.
> Or maybe sorting lists of lists is just such a rare op that no one has
> ever encountered it before me?
It would be useful to have a total ordering on Lisp values: for heterogeneous
ordered collections, for simplifying multi-key sorting, for normalising
unordered collections, etc.
The devil is in the details: are strings compared with our without properties?
Do we observe the wonky IEEE rules for ordering floats? Is there a particularly
useful ordering between elements of different types? Do we need to worry about
circularity? How do we compare hash tables? And so on.
Consistency with `equal` would be desirable (up to hash table identity,
perhaps).