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Re: Displaystyle and mtable

From: Karl Tomlinson <w3@karlt.net>
Date: Thu, 12 Jun 2014 09:18:00 +1200
To: David Carlisle <davidc@nag.co.uk>
Cc: <www-math@w3.org>
Message-ID: <87fvjbxi0n.fsf@karlt.net>
David Carlisle writes:

> On 11/06/2014 16:59, Frédéric WANG wrote:
>> where we expect the content to inherit displaystyle. In any
>> case, it seems that the spec should be clarified. 
>
> Clearly if people are misreading it it could be clearer
> (or at least a clarifying text could be added somewhere such as an
> errata document)
> But at present I'm not sure what should change.
>
> the attribute table
>
> http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.mtable.attrs
>
> explicitly lists the default as "false"
>
> and the text just after that table highlights this again:
>
>> The |displaystyle| attribute is allowed on the |mtable| element
>> to set the inherited value of the attribute. If the attribute is
>> not present, the |mtable| element sets |displaystyle| to "false"
>> within the table elements
>
> I suppose the only thing that could be said is that mtable is not
> mentioned in 3.16 where it says
>
>> They are automatically adjusted by the various script and limit
>> schemata
>> <http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.scrlim>
>> elements, and the elements |mfrac|
>> <http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.mfrac>
>> and |mroot|
>> <http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.mroot>,
>> which typically set |displaystyle| false and increment
>> |scriptlevel| for some or all of their arguments. (See the
>> description for each element for the specific rules used.) 
>
> Although that's just a pointer not an exaustive list and anyway
> ends in (See the description for each element for the specific
> rules used.) which covers everything:)
>
> Is this the part that you think should be clarified?  a minimal
> change being to say
>
> ... and the elements |mtable, mfrac|
> <http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.mfrac>
> and |mroot|
> <http://www.w3.org/Math/draft-spec/mathml.html#chapter3_presm.mroot>,

The part that seems inconsistent to me is 

  "They also may be set explicitly via the displaystyle and
  scriptlevel attributes on the mstyle element or the displaystyle
  attribute of mtable. In all other cases, they are inherited from
  the node's parent."

because "explicitly" here also applies to "displaystyle
attribute of mtable", and "all other cases" seems to imply that
the previous sentences form an exhaustive list.
A default (not explicit) attribute of mtable was not in the
exhaustive list.

Perhaps removing "explicitly" might be enough to remove the
inconsistency.
Received on Wednesday, 11 June 2014 21:18:36 UTC

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