Hi,
- "Tools" is pluralized, while "Dialog" and "Widget" are not. This is
inconsistent. Actually, there's two namespaces: Inkscape::UI::Dialog und Inkscape::UI::Dialogs. So it has never been consistent ;) .
In general, 2 levels of namespaces are entirely sufficient. XML tree goes
into Inkscape::XML, UI code goes into Inkscape::UI, object (SP) tree goes into Inkscape::SVG (in the future), and so on. I'd suggest using the same hierarchy in namespaces that is used for the directories. So when something is put in src/ui/widgets, then the code should be in the namespace Inkscape::UI::Widgets. That's how other languages handle this as well and I think that's not a bad idea. You may use a "using" in you cpp files, that's not a problem. And if you need to many of them, think of whether you can split up the file. If the code is cleanly separated into several layers, then there are not too many dependencies.
Regards, Markus