[cmake-developers] Natvis support in Visual Studio

[Robert Dailey]

Hello CMake devs,

I'm writing code to support Natvis files in Visual Studio 2015
(earlier versions support this as well, I think).

I found an issue regarding this here (is Kitware officially using
github or gitlab? CMake exists on both):
https://gitlab.kitware.com/cmake/cmake/issues/16043

Corresponding link on mantis (deprecated?):
https://cmake.org/Bug/view.php?id=16043

I have some questions. It's not straightforward on  how to implement
this. In cmVisualStudio10TargetGenerator, there is a WriteAllSources()
function which seems to do 2 main things. It seems to look up things
mapped to object files and call WriteSource() on each of those.
Currently it seems to support C, CXX, MASM, and RC language types.
Then there is WriteExtraSources(), which I can only assume is
"everything else". Is this correct?

If I am correct, would I also be correct to assume that
WriteExtraSource should be the one to set the XML element name
(<Natvis>) for *.natvis files based on LANGUAGE being set to NATVIS?
To add to this confusion, cmVisualStudio7Generator::WriteGroup() seems
to do the file extension to LANGUAGE mapping, and I can't tell if the
VS10 generator class is also sharing this code. If it is, do I extend
that function in the VS10 generator class for *.natvis files?
Somewhere I need to be able to automatically set the LANGUAGE property
based on file extension.

Guidance is appreciated!