TYPO3 Core

Actually, this is a BIG feature request. At the moment it is imho impossible even with realurl to map a domain to a specific language and vise versa.
Yes, you can set ONE domain to a language but not independently of other domains. Either you use that "feature" for ALL domains or for none but a mix is not possible.

What i want is something like that:

www.example.de -> L=0
www.example.com -> L=1
www.example.com/fr -> L=2

Now with basic realurl this is NOT possible since it is not possible to map one domain to 2 different languages.

There are customers who want to have only the de domain for german language and the .com domain for the rest. i know this is not good for SEO reasons.

what i am doing at the moment is to disable the domain thing for realurl for some language to make that HALF work. The language menu (standard TYPO3) simply adds the wrong baseurl for the other languages if i am on the de domain, then the domains look like:
www.example.de/fr but it should be www.example.com/fr.

This domain-language mapping must to take place in the core for the typolink function and the "special" typolink function in the menu generation.

oh by the way, multi tree & multi language system so this also has to work across page trees.