Question

I have an XML document, part of which has the following in it:

<math display='block'><mtext>&#x2009;</mtext></math>

If this is loaded into Qt (specifically the Qt MathML widget where I found this problem), the QDomDocument object loses the unicode thin space character (U+2009). This Python example code demonstrates the problem:

from PyQt4.QtXml import *

d = QDomDocument()
d.setContent("<math display='block'><mtext>&#x2009;</mtext></math>")
print repr(unicode(d.toString()))

The output from this code is:

u'<math display="block">\n <mtext/>\n</math>\n'

Inserting an extra non-space character after the thin space stops the thin space being lost.

Is this my mistake, an XML feature, or does Qt have a bug?

Answer 1

From QDomDocument’s documentation:

Text nodes consisting only of whitespace are stripped and won’t appear
in the QDomDocument. If this behavior is not desired, one can use the
setContent() overload that allows a QXmlReader to be supplied.

So this way you do not lose the white space only data (example is in C++):

QXmlSimpleReader reader;
QXmlInputSource source;
QDomDocument dom;

source.setData(QString("<mtext>&#x2009;</mtext>"));
dom.setContent(&source, &reader);