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RE: Case sensitivity of unit identifiers

From: Robert Miner <robertm@dessci.com>
Date: Fri, 30 Nov 2007 09:36:18 -0800
Message-ID: <D1EFB337111B674B8F1BE155B01C6DD60282A591@franklin.corp.dessci>
To: "L. David Baron" <dbaron@dbaron.org>, <www-math@w3.org>

Dave,

After a little back channel discussion with the WG, the consensus opinion is that they are case sensitive and lower-case.  That is partly based on current practice in most implementations, and that in general MathML 2 is case sensitive, with the few exceptions being clearly noted, as you point out.

The general rule about case sensitivity doesn't seem to be explicit anywhere I could find either.  However, David Carlisle notes:

  The current draft of MathML3 (both the public one and
  our internal draft) have exaxt same wording for that section. We should
  clarify this.

  > Am I missing something?  Or would errata to the spec be useful here?

  Not sure that an errata is needed but we should clarify what the
  position is  in MathML3.

  In MathML2 the DTD is normative (as well as the text) and obviously
  can't enforce anything here however there is a non-normative schema
  file:///C:/w3c/WWW/Math/xmlschema/mathml2/presentation/common-types.xsd
  which says
  <xs:simpleType name="length-with-unit">
    <xs:restriction base="xs:string">
      <xs:pattern value="(-?([0-9]+|[0-9]*\.[0-9]+)*(em|ex|px|in|cm|mm|pt|pc|%))|0"/>
    </xs:restriction>
  </xs:simpleType>
  thus forcing lower-case.

  In MathML3 we will (probably) have a normative Relax Schema which could
  have a similar pattern, although currently it just says xs:string.
  Clearly the regexp would have to be extended to the case insenitive
  equivalent if that _is_ what was intended.

Hope this helps.  Certainly feel free to advocate for how you think it should be in MathML 3.  The Mozilla implementation of MathML is really important to us all.

--Robert

Robert Miner
Vice President, Research and Development

Design Science, Inc.
140 Pine Avenue, 4th Floor
Long Beach, California  90802
USA
Tel:  (651) 223-2883
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robertm@dessci.com
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~ Makers of MathType, MathFlow, MathPlayer, WebEQ, Equation Editor, TexAide ~


> -----Original Message-----
> From: www-math-request@w3.org [mailto:www-math-request@w3.org] On Behalf
> Of L. David Baron
> Sent: Thursday, November 29, 2007 5:03 PM
> To: www-math@w3.org
> Subject: Case sensitivity of unit identifiers
> 
> 
> I'm trying to figure out whether unit identifiers in MathML are
> case-sensitive or case-insensitive (e.g., whether '3PX' is
> equivalent to '3px', as it is in CSS), but I can't find a clear
> answer in the spec.
> 
> http://www.w3.org/TR/2003/REC-MathML2-
> 20031021/chapter2.html#fund.xmlsyntax
> says that all MathML element and attribute names are case-sensitive,
> but doesn't mention attribute values.  (A general statement
> somewhere about attribute values might be useful.)
> 
> http://www.w3.org/TR/2003/REC-MathML2-20031021/chapter3.html#presm.color
> says that hexidecimal color values and named color keywords are not
> case sensitive (as an exception to a general rule that I haven't
> found stated anywhere else).
> 
> http://www.w3.org/TR/2003/REC-MathML2-20031021/chapter2.html#fund.units
> says "The unit identifiers and meanings are taken from CSS."  Does
> that imply that the case-sensitivity is also taken from CSS?  It's
> not clear to me, since the section goes on to define a number of
> differences with CSS and explicitly define a number of things that
> *are* taken from CSS.
> 
> Am I missing something?  Or would errata to the spec be useful here?
> 
> -David
> 
> --
> L. David Baron                                 http://dbaron.org/
> Mozilla Corporation                       http://www.mozilla.com/
Received on Friday, 30 November 2007 17:37:05 GMT

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