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Re: those predeclared entity refs



davep@acm.org (Dave Peterson) wrote:
> lee@sq.com wrote:
> >Perhaps we also need apostrophe and grave accent.  Note that there
> >is no single quote in ASCII, as ' is an apostrophe and ` is a grave
> >accent.  The typewriter doube quote (") makes the fifth, right?
> >
> >amp     ampersand                 &
> >lt      left angle bracket        <
> >quot    grave accent              `
> >apos    apostrophe                '
> >dquot   typewriter double quote   "
> >
> >That makeds five; do we also need
> >gt      right angle brcket        >
> >or
> >ket     right bracket             ]
> 
> Does Unicode or 10646 really define "<" and ">" as left and right
> angle brackets?
No -- I was writing from home, sorry.
They are GREATER THAN and LESS THAN.

> Same question about "`".  Really just a stand-alone accent?

UNICODE has ' (0027) as APOSTROPHE-QUOT
and         ` (0060) as SPACING GRAVE

> What authority says that the &quot entity is "`"? 

My faulty memory.  Actually different SGML sources give &quot;
to be ' or ", which doesn't help (e.g. Joan Smith, an authority but
not authoritative) gives quot as " and since the standard didn't
give pictures, nor the handbook, that's how I've always used it.

> I know of systems whose character
> repertoires differentiate between apostrophe and single closing quote!
Yes, that's resonable.  In display work the single quote is often
rendered more heavily.

> and neither one is the "typwriter single quote" that "'" was at
> least originally meant to be.

Well, ASCII has it as an apostrophe, I believe.

> I assume you just made up "ket" as a name for "]"?
No, it's a common computer science name: bra and ket, [ and ].

>  o   Do the implied entity definitions for &amp, &lt, and &gt (the
>      current required set) take precedence over local ones?  Currently
>      they do.  (And *currently* must, see next bullet.)
> 
>  o   Is the user *required* to use these three to escape "&", "<",
>      and ">", rather than any other entities he or she may have
>      available, or even other mechanisms for escaping?  As I read
>      the Nov 96 spec, this is a requirement.  I don't like it.
> 
> BTW, the spec says that you are to escape "]]>" as "]]&gt;".

Someone else gave the 5 names.  The spec isn't up to date, so I didn't
check against it, sorry.

If the names are part of the language they must begin with XML-.

If you can override them, they should not begin with XML-.

If you override them and do not have a DTD, you're OK to the
same extent you are with any other entity.

I don't see how you can forbid other entities to have replacement values
of & or < or " --- and that would be the effect of your second bullet
point --- so that must surely be an error in reading?

Lee