Re: `append' vs. `nconc'

[Emanuel Berg]

"Pascal J. Bourguignon" <pjb@informatimago.com>
writes:

> You must remember the literal/immutable status of
> each item at each level.
>
> Since you are incapable of remembering it, you
> should assume that the whole input data is immutable
> and write purely functional code (ie. use append,
> not nconc) in general.

OK, so you use `nconc' when you yourself create the
lists by hand and thus know they are not empty, all
the while using `list' and not ', and when done you
assign the result to a variable associated with a list
INSTEAD of using `nconc' directly because that
variable can hold the empty list, i.e. nil, which
`nconc' contrary to `append' cannot handle. And you do
this to save time!

Now I got it right!

-- 
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