[Katsunami]

What does it matter, if functionality similar to Sigil's will end up in Calibre, and that it is not a seperate program? You can just create a "Workspace" library, import you texts in there, and open them in the editor. Then work with them as you would with Sigil itself. Instead of opening the file from your desktop, you'd open it from your workplace library.

It's the same approach as Lightroom takes for pictures, and it works very well there. There are a lot of people who use Lightroom as a library only, as a photo editor only, or both, myself included. There is no reason that Calibre cannot be used in the same way.

While I understand the apprehension against this approach (it does yield some sort of "hybrid" program, half of which is not useful for the task you intend to do), there are also a lot of advantages. Any improvement in Calibre's EPUB2 / EPUB3 support will automatically be available in the editor (or with relatively little changes) as it uses the same input/output plugins. Any improvement in a function in Calibre that impacts the editor in some way, such as metadata editing, will automatically be an improvement in the editor. Coding in Python will be much faster and much more productive than in C++, yielding much faster bugfixes and more rapid implementation of requested functionality.

I think that the chances of a calibre-hosted editor catching up with Sigil, and eventually overtaking it at some point are MUCH better than finding someone willing to look into EPUB2/EPUB3 coding, the BOOST library, QT in C++, and so on, just to maintain and extend a seperate program for a very small niche of people.