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Re: menclose: several values in the "notation" attribute

From: Karl Tomlinson <w3@karlt.net>
Date: Tue, 20 Jan 2009 16:19:46 +1300
CC: "Neil Soiffer" <Neils@dessci.com>
Cc: Frédéric WANG <fred.wang@free.fr>
To: www-math@w3.org
Message-ID: <87hc3uoe99.fsf@blackhawk.home>

On Fri, 14 Nov 2008 21:01:15 -0800, Neil Soiffer wrote:

> The spec currently says
> "Any number of values can be given for notation separated by whitespace; all
> of those given and understood by a MathML renderer should be rendered. For
> example, notation="circle horizontalstrike" should result in circle around
> the contents of menclose with a horizontal line through the contents. "
>
> That seems pretty clear to me that all of the values should be rendered.  It
> is maybe less clear that they should overlap, but the paragraphs that give
> default spacing from the content, so that is pretty strongly implied just as
> it is in the text above.  Is it really necessary to add something that say
> they should overlap?

What is perhaps not clear is whether or not "contents" or
"content" includes the notations.  Most of
http://www.w3.org/TR/2008/WD-MathML3-20081117/chapter3.html#presm.menclose
seems to imply that "contents" are its arguments (child elements),
but not the notations.  This is most strongly suggested here:

  menclose accepts any number of arguments; if this number is not 1,
  its contents are treated as a single "inferred mrow" containing
  its arguments, ...

The one thing that seems contradictory to this interpretation of
"content" is the example in this statement:

  The values "updiagonalstrike", "downdiagonalstrike",
  "verticalstrike" and "horizontalstrike" should result in the
  indicated strikeout lines being superimposed over the content of
  the menclose, e.g. a strikeout that extends from the lower left
  corner to the upper right corner of the menclose element for
  "updiagonalstrike", etc.

Assuming the "menclose element" includes the notations, a
strikeout from "the lower left corner to the upper right corner of
the menclose element" would strikeout other notations as well as
child elements.

However, an interpretation that includes the notations in the
contents also could not be consistent, because it would not be
possible to have both "roundedbox" and "circle" enclose other each
other, nor could they enclose a updiagonalstrike, while that
updiagonalstrike strikes out the roundedbox or circle.

As most of the section seems to use "content" and "contents" to
refer only to child elements, not notations, I expect that it's
best not to infer too much from the "updiagonalstrike" example?

If so, I would suggest changing the wording to avoid using the
expression "menclose element".  Perhaps

  e.g. a strikeout that extends from the lower left corner to the
  upper right corner of a rectangle enclosing the child elements
  for "updiagonalstrike", etc.
Received on Tuesday, 20 January 2009 03:20:31 GMT

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