Re: gnus should accept UTF8 even if UTF-8 is standard

[Kenichi Handa <handa@m17n.org>]

In article <E1KvziI-0005Qf-30@fencepost.gnu.org>, "Richard M. Stallman" <rms@gnu.org> writes:

>     In the case of filenames, there surely exist the actual file
>     with those ignored extensions.  But, in the case of coding
>     systems, such an alias as "utf8" doesn't exist.  Or do you
>     still propose to make such an alias as a sencond-class name
>     in advance?

> To define them as second-class extensions would be one method.
> Another is this: `read-coding-system' could create the completion
> alist, then add to it modified entries made by replacing "utf-8" with
> "utf8".  Then it could read the name, using the appropriate kind of
> completion.  When it gets back the value from `completing-read', it
> could replace "utf8" with "utf-8".

> This avoids having a list of second-class "utf8" aliases.  Those
> aliases would be constructed automatically from the valid names
> that start with "utf-8".

> 		 If so, I strongly oppose to it.

> Why, what harm would it do?

With that, people think that "utf8" is a valid coding system
name, and will write a code something like this:
  (decode-coding-string STR 'utf8)
and found that it signals an error because utf8 is not
statically declared as an alias.

>       If we are
>     going to allow users to type all names that are accepted by
>     iconv, we must make so many aliases.

> I don't know which names are accepted by iconv, so I don't know
> whether I'm in favor of accepting them all.

> But suppose that we decide to accept them all, and suppose we decide
> to do it by defining each one as a second-class alias.  How many
> second-class aliases would that require?

For instance, "% iconv -l", lists these variants for
iso-8859-1:

"ISO-8859-1", "ISO88591" "8859_1", "ISO_8859-1"

In addition, we must add (partial) lowercase versions.
Partial means something like this: Iso ISo isO

And, as we also have to add "-dos", "-unix", "-mac"
variatants.

So total aliases we'll add are more than 100 just for
iso-8859-1.

And, the "iconv" program actualy accepts any pattern
matching with "iso[^a-zA-Z0-9]8859-1"; e.g. "iso 8859-1",
"iso=8859-1", etc.

Considering them, it is not realistic to have all aliases
statically.

---
Kenichi Handa
handa@ni.aist.go.jp