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Re: [MathML3-last-call] mathvariant

From: Sam Dooley <sam@integretechpub.com>
Date: Tue, 13 Oct 2009 17:18:20 -0600
Message-Id: <200910132319.n9DNJOdS014742@parzival.integretechpub.com>
To: "William F. Hammond" <hammond@math.albany.edu>, www-math@w3.org

Thanks also for your comments.

At 03:38 PM 10/13/2009, William F Hammond wrote:
>Sorry, I've not really been following this, but several things
>in this thread today have grabbed me.
>Karl Tomlinson <w3@karlt.net> writes:
>> . . .
>>> Note that the appearance
>>> of a mathematical alphanumeric symbol character should not be altered
>>> by surrounding <att>mathvariant</att> or other style declarations.</p>
>Is the meaning here of 'other style declarations' limited to MathML
>markup or does it extend to CSS?  I think it should not extend to CSS.

This language does extend to include CSS.  If an author encodes
<mi mathvariant="bold">v</mi> or <mi>&#x1D42F;</mi>, they should
get a bold lower-case v.  A style sheet could be used to specify
which font is used to display bold characters, but it should not
change the weight or shape of the character.

>> . . .
>>> Renderers may ignore or support those combinations of character data
>>> and <att>mathvariant</att> values that do not correspond to an assigned
>>> Unicode code point,
>> ... and this sentence says "may", implying that the better
>> behavior for renderers is to alter the appearance of all
>> non-mathematical-alphanumeric-symbol characters according to the
>> mathvariant attribute when possible.
>In view of the 2nd paragraph below I'm confused.  Is it thought
>correct to use 'mathvariant' for switching on, for example, italic

No, mathvariant is not about applying style, it is about applying semantics,
that is, creating math symbols that carry meaning via style that should
be protected from other style changes.

>> This would be a change from MathML2, so I just want to check that
>> this has been thought through.
>> This would effectively mean that almost all
>> non-mathematical-alphanumeric-symbol characters in an mi element
>> without an explicit mathvariant attribute should be rendered in an
>> italic form.
>(Is it clear what portion of 'mathematical-alphanumeric' is negated
>by the 'non'?)
>As I have understood things, a string matching the pattern /^[A-Za-z]$/
>(i.e., a single alphabetic character) inside an mi should by default be
>rendered italic, but a string matching the pattern /^[A-Za-z][0-9A-Za-z]+$/
>should by default be rendered upright.  This is a long-standing tradition
>in mathematical typesetting.  I hope you're not suggesting this would change.

mi with a single character should still use mathvariant italic.
mi with more than one character should still use mathvariant normal.
This situation has not changed from MathML 2.

>> One example to consider is U+221E INFINITY.  ...
>With other strings inside an mi my own inclination would be to
>be explicit about style -- and I mean style, not character casting --
>if I care which way it is set.  Again I ask if the MathML attribute
>'mathvariant' is the correct thing to use for that.  CSS is for style.
>Isn't mathvariant provided for character casting, i.e., pointing to a
>character other than that inside the mi?

I think we are saying the same things here:  CSS is for style,
mathvariant is for creating symbolic math identifiers, not for styling.
Whether or not you view mathvariant as a Unicode to Unicode map is an
implementation detail, since implementations are allowed to support
combinations that do not correspond to Unicode code points.

>> . . .
>> One thing that concerns me is that, although we now have better
>> Unicode support for mathematical characters than ever, there seems
>> to be an increased expectation of creating characters by other
>> means that resemble style.
>While I do see (and understand) avoidance of the more esoteric reaches
>of unicode, e.g., plane 1, I think the tools of avoidance should not
>be style.  As I've said, I don't see mathvariant as stylistic.
>                                    -- Bill

Agreed, the tool of avoidance (mathvariant) is not intended to be
about style.

Received on Tuesday, 13 October 2009 23:20:07 UTC

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