unwise uses of `length' [was: Internationalize Emacs's messages (swahili)]

[Drew Adams]

All: Please think of changing the Subject line
when the topic changes, especially for a radical
change such as this one.  Thx.
___

As for this topic, I think no special addition
to the language is needed.  This is just a
gotcha that users need to learn.  And it's not
really specific to Lisp, even if Lisp makes
heavy use of cons-constructed lists.
___

If not already there, we could add mention of
this to, say, the Elisp Lisp Intro book, or
perhaps even the Elisp manual.  Our manuals
do contain some user guidance, even those
manuals that have mostly reference material.

(And that's a plus, IMO, not a minus.  Manuals
that are only API lists aren't so helpful.)