Re: Emacs Lisp's future

[David Kastrup]

Eli Zaretskii <address@hidden> writes:

>> From: David Kastrup <address@hidden>
>> Cc: address@hidden, address@hidden, address@hidden,
>> address@hidden, address@hidden, address@hidden,
>> address@hidden
>> Date: Thu, 09 Oct 2014 09:52:31 +0200
>> 
>> I still don't want the autosave of mail to complain about bad
>> characters.
>
> We write the auto-save files in the internal format, so it never
> complains.

If you are not allowed or able to do that...  At the current point of
time, the only round-trippable encoding for bytes that GUILE offers is
latin-1, and the only round-trippable encoding for characters is utf-8.

The conceptual lack of separation between internal and external utf-8
encoding leads to strangenesses like

scheme@(guile-user)> (with-input-from-string "\ufeff!" read-char)
$8 = #\!

Yes, this is a string->string operation losing a byte order mark in
spite of no indication that I would like to get encodings involved in
any manner.

Now we'll probably get "oh, that's a bug, we'll fix it".  But the point
is that being sloppy with the distinction between internal and external
character sets and encodings and "valid" and "invalid" will buy you
unmatched encoding/decoding passes inviting such problems.

And when I can say "let's see where this kind of thinking will lead" and
find a hole to poke within a minute, so will malicious people.  And that
is a real security concern.

Also: if I do not even manage to save a string into a string in "the
internal format" unchanged, good luck with your auto-save file.

-- 
David Kastrup