Re: Doc: typo in config.sgml

On Wed, Oct  9, 2024 at 11:49:29AM +0900, Tatsuo Ishii wrote:
> >> On Mon, Sep 30, 2024 at 11:59:48AM +0200, Daniel Gustafsson wrote:
> >> > > On 30 Sep 2024, at 11:03, Tatsuo Ishii <ishii@postgresql.org> wrote:
> >> > > 
> >> > >>>> I think there's an unnecessary underscore in config.sgml.
> >> > > 
> >> > > I was wrong. The particular byte sequences just looked an underscore
> >> > > on my editor but the byte sequence is actually 0xc2a0, which must be a
> >> > > "non breaking space" encoded in UTF-8. I guess someone mistakenly
> >> > > insert a non breaking space while editing config.sgml.
> >> > 
> >> > I wonder if it would be worth to add a check for this like we have to tabs?
> >> > The attached adds a rule to "make -C doc/src/sgml check" for trapping nbsp
> >> > (doing so made me realize we don't have an equivalent meson target).
> >> 
> >> Can we check for any character outside the support range of SGML?
> > 
> > What we can define the range of allowed characters range in SGML?
> > 
> > We can detect non-ASCII characters by using regexp /\P{ascii}/ or /[^\x00-\x7f]/,
> > but they are used in some places in charset.sgml and some names in release-*.sgml.
> 
> I failed to find any standard regarding what characters are allowed in
> SGML/XML. Assuming that any valid Unicode characters are allowed in
> our *sgml files, I am afraid the best we can do is grepping non-ASCII
> characters against the files and checking the results by a visual
> inspection. Besides nbsp, there are tons of confusing Unicode
> characters out there. For example there are many "hyphen like
> characters".
> 
> https://www.compart.com/en/unicode/category/Pd
> 
> If one of them is used in the sgml files, it may be possible that it
> was accidentally inserted.

Can we use Unicode in the SGML files?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

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