Hi,

Yesterday I had an interesting bug in a piece of code that applied a
stylesheet to a XML document. The input document used some "special"
characters (specifically the symbol for micro - which was specified in
the input XML as µ). The stylesheet was being used to convert the
input XML to Excel's SpreadsheetML. To make a long story short, the
micro used to disappear when viewed from XML.

We we using ActiveX and MSXML 4.0.

We spent almost half a day trying to figure out what was going wrong,
and finally tracked it down the code that applied the stylesheet - the
buggy code used to look like this

...
outXMLString = inputDoc.transformNode(stylesheet)
' Code to write outXMLString to a file
...

The input XML was something like this: (The micro was being used as in
the unit Micro Amperes)

<Stuff>
<Data>
&#181;A
</Data>
</Stuff>

And the XSLT was something like this:

...
<xsl:value-of select="./Data" />
...

The problem was that the &#181; used to come out as a single character.
(A lot of digging around revealed that you need two characters to
represent micro - C2 B5 rather than just B5 - btw B5 is 181 represented
in hex) Some applications - like Excel - would just pretend that the
character wasn't there. Some others - like Visual Studio, Firefox would
show a helpful little question mark instead of the character - and some
others - like VIM would actually render it as micro.

Me not knowing too much about character encodings - having dealt with
ASCII all my life - was about as confused as I could. But after trying
this, that and everything else, with thanks some kind hearted souls on
Usenet, found that changing the code that applied the stylesheet to
look like this:

...
inputDoc.transformNodeToObject(stylesheet, outputDoc)
outputDoc.save(filename)
...

would fix the problem.

My question to any wise and helpful souls out there is pretty simple:
Why does this work, while the old one doesn't? My current guess is that
this has something do with how the string coming out transformNode is
encoded, but I don't really understand the details.

Can you guys help out please?