W3C home > Mailing lists > Public > www-math@w3.org > January 2001

Re: DoubleLongLeftArrow character entity

From: David Carlisle <davidc@nag.co.uk>
Date: Thu, 11 Jan 2001 17:05:03 GMT
Message-Id: <200101111705.RAA03798@penguin.nag.co.uk>
To: hammond@csc.albany.edu
CC: www-math@w3.org, mozilla-mathml@mozilla.org

> Long arrows arise in academic journals in many disciplines.

They are also in the ISO Mathematical entity collections that formed the
basis of the MathML character names.

> So why were they left out of unicode?


Well I suppose the answer is that Unicode think that the length
of an arrow is a stylistic thing that should be done in markup.

> Have such needs been considered?

It's inevitable that a finite list like Unicode (for a fixed release
number) will have these problems somewhere. Personally I think that
after unicode 3.1 and 3.2 are ratified, Mathematics will be in a much
better position than it was previously. The fact that some characters
that "clearly" ought to be in are not in, and some characters that are
in have dubious utility is not surprising (and which characters are in
these sets will depend on who you ask:-) But these are minor problems
around the edges and taking the character proposals as a block, they are
a good thing and we should welcome them.

> I hope this does not mean that one will need to resort to SVG images
> for new glyphs.
Well in MathML you could use mglyph to refer to a glyph via font and
number, you'd only need SVG if you were really drawing some one off
shape you'd just invented.

> It's not just about MathML.
true. In fact in this case it is not really MathML at all. The choice of
characters that gets into Unicode is really a Unicode/ISO decision.
The MathML group may be consulted but it's an important division of labour
that they specify the Character set and W3C specifies the markup.


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Received on Thursday, 11 January 2001 12:05:21 UTC

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