662756 - The default value for attributes lspace/rspace of <mo> should be thickmathspace

Status: RESOLVED FIXED

(Core :: MathML, defect)

Description

[Frédéric Wang (:fredw)]

The MathML REC says that the default values are "thickmathspace":

http://www.w3.org/TR/MathML/chapter3.html#presm.mo.attrs

In general, people use operators that are in our dictionary, so that's not a problem.

Comment 1

[Frédéric Wang (:fredw)]

Here is an example in the MathML testsuite where we can see a problem:

http://www.w3.org/Math/testsuite/build/main/Presentation/TokenElements/mo/mo6-full.xhtml

Comment 2

[Frédéric Wang (:fredw)]

I'm guessing we only need to initialize lspace and rspace to the value of thickmathspace instead of 0 here:

http://mxr.mozilla.org/mozilla-central/source/layout/mathml/nsMathMLmoFrame.cpp#386

Comment 3

[Frédéric Wang (:fredw)]

(In reply to comment #1)
> Here is an example in the MathML testsuite where we can see a problem:
> 
> http://www.w3.org/Math/testsuite/build/main/Presentation/TokenElements/mo/
> mo6-full.xhtml

the same converted into reftest:

https://github.com/fred-wang/MathJax-test/blob/master/MathMLToDisplay/Presentation/TokenElements/mo/mo6.html
https://github.com/fred-wang/MathJax-test/blob/master/MathMLToDisplay/Presentation/TokenElements/mo/mo6-ref.html

Comment 4

[Jonathan Hage]

Attachment: Testcase

Comment 5

[Jonathan Hage]

Attachment: Patch add thickmathspace

Comment 6

[Jonathan Hage]

For both tests, we can see that the result is what we expected. But, with the tests proposed by Frédéric Wang, we can note there is a space not expected between f and (x). The applyfunction is treated like an mo that is not in the dictionary. If I comment the following condition: 
 http://mxr.mozilla.org/mozilla-central/source/layout/mathml/nsMathMLmoFrame.cpp#182
the result is good. But there is a new problem, because the line is more below than the line of the reftest but I don't know why.
To finish we can ask ourselves what we can do if the mo is not in the dictionary and at the beginning of the line. It would be better that the space shouldn't appear at the left of the mo.

Comment 7

[Frédéric Wang (:fredw)]

Attachment: Patch V2

Comment 8

[Frédéric Wang (:fredw)]

Attachment: Reftest

Comment 9

[Frédéric Wang (:fredw)]

https://tbpl.mozilla.org/?tree=Try&rev=9bfe662cd66a

Comment 10

[Karl Tomlinson (:karlt)]

I assume that, if the scriptlevel and IS_ISOLATED tuning is appropriate for
l/rspace from the dictionary, it would also be appropriate for default values.

An implementation that changed the initialization of the lspace and rspace
variables to the 5/18 default would be simpler and keep this tuning.
Is there a reason why you wanted to avoid the tuning?

Comment 11

[Frédéric Wang (:fredw)]

(In reply to Karl Tomlinson (:karlt) from comment #10)
> An implementation that changed the initialization of the lspace and rspace
> variables to the 5/18 default would be simpler and keep this tuning.
> Is there a reason why you wanted to avoid the tuning?

Yes, that's what I was wondering too. I don't have a strong reason, except trying to follow the MathML spec (but even thickmathspace = 5/18 is only a recommended value and I know that MathJax does not always follow the spacing recommended by the spec). I'll keep the tuning.

(In general, I don't find this bug too important in practice, but it is a test in the MathML testsuite)

Comment 12

[Frédéric Wang (:fredw)]

https://tbpl.mozilla.org/?tree=Try&rev=0a69b393ff4a

Comment 13

[Karl Tomlinson (:karlt)]

Comment on attachment 630247 [details] [diff] [review]
Patch V2

(Comment 10)

Comment 14

[Frédéric Wang (:fredw)]

Attachment: Patch V3

I forgot to update my patch sorry. The previous Try Server results in comment 12 was for this new version.

Comment 15

[Jared Wein [:jaws] (please needinfo? me)]

Pushed to mozilla-inbound:
https://hg.mozilla.org/integration/mozilla-inbound/rev/08f12e27bf51
https://hg.mozilla.org/integration/mozilla-inbound/rev/ef4be3efbb41

Comment 16

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/08f12e27bf51
https://hg.mozilla.org/mozilla-central/rev/ef4be3efbb41

Comment 17

[Mozilla RelEng Bot]

Autoland Patchset:
	Patches: 630248, 635743
	Branch: mozilla-central => try
Patch 630248 could not be applied to mozilla-central.
file layout/reftests/mathml/mo-lspace-rspace-ref.html already exists
1 out of 1 hunks FAILED -- saving rejects to file layout/reftests/mathml/mo-lspace-rspace-ref.html.rej
file layout/reftests/mathml/mo-lspace-rspace.html already exists
1 out of 1 hunks FAILED -- saving rejects to file layout/reftests/mathml/mo-lspace-rspace.html.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working dir

Patchset could not be applied and pushed.

Comment 18

[Florian Scholz (Open Web Docs)]

https://developer.mozilla.org/en-US/docs/Firefox_16_for_developers#MathML
https://developer.mozilla.org/en-US/docs/MathML/Element/mo#Gecko-specific_notes