- From: Bruce Rosenblum <bruce@inera.com>
- Date: Thu, 12 Nov 2009 15:59:44 -0500
- To: David Carlisle <davidc@nag.co.uk>
- Cc: www-math@w3.org,btusdin@mulberrytech.com,dalapeyre@mulberrytech.com
David, Thanks for the clear and complete explanation. It's helpful, and I appreciate your time to reply. Best regards, Bruce At 12:45 PM 11/12/2009, David Carlisle wrote: > > Shouldn't this be defined as: > > > > <!ENTITY lowast "⁎" ><!--low asterisk --> > >One might expect that, but like some others (most notably asymp) the >definitions are somewhat skewed by html compatibility. Many of the html4 >entity definitions are somewhat strange but the html4 symbol.ent file >linked from > >http://www.w3.org/TR/html4/sgml/dtd.html > >defines lowast to be > ><!ENTITY lowast CDATA "∗" -- asterisk operator, U+2217 ISOtech --> > >The html entity sets are baked into code in multiple browsers of every >desktop and mobile phone on the planet and nothing that is put in a dtd >entity file will change that as most html systems don't read these >definitions from any kind of declarative file, thus is seems futile to >publish an html dtd with definitions different from the ones actually >implemented, and it would be odd to try to make xhtml incompatible to >html with respect to entity definitions. > >If the mathml set were incompatible with xhtml then the meaning of lowast >throughout an xhtml+mathml document would depend on the technical >details of how the dtds were combined, but whichever definition "won" it >would mean the same thing throughout the document, you can't make the >expansion of the entity sensitive to which element the entity is in. > >The main aim of taking the entity set definitions out of mathml into >their own spec at > >http://www.w3.org/TR/xml-entity-names/ > >is to get a common set of definitions that can be used accross >languages, but where existing usage in different communities is >incompatible, getting a common set means something has to change and the >above considerations mean that essentially if there was a conflict the >html definition was taken. > >I hope that explains why things are as they are > >David > >________________________________________________________________________ >The Numerical Algorithms Group Ltd is a company registered in England >and Wales with company number 1249803. The registered office is: >Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom. > >This e-mail has been scanned for all viruses by Star. The service is >powered by MessageLabs. >________________________________________________________________________ ------------------------------------------------------------------- Bruce D. Rosenblum Inera Inc. 815 Washington St. #3 Newton, MA 02460 617-969-3053 (office) 617-969-4911 (fax) bruce@inera.com
Received on Thursday, 12 November 2009 21:00:32 UTC