Originally Posted by Jellby
In reality, I'd prefer not to have to include these thin spaces. In LaTeX, for instance, I can just say that I'm writing in French, and automatically all punctuation that needs has some space (non-breaking, of course) added before/after it. I wish there was something similar for ePub (and there's no reason why a rendering engine could not implement it).
It would be great. I will ask Henrik Just about it. He is probably familiar about it because he develops Writer2Latex, of which W2X is only a subset.
Thanks for your other answers.