Hello,
[...]
We could support them right now in parallel with the old ones and obsolete +, == and != for strings in the future (but that means we still cannot optimize '+' in all the cases) or switch right now (maybe with some old compat switch which will support old scripts style).
I'd prefer to not introduce too much compatibility layers, this makes debugging and maintaining both the code and the config script more harder then necessary in my experience.
I agree here. Although we aim to have full compatibility with K and S configs, I am looking at it more as functionality, not as syntax. I am using this opportunity for doing cleanups and removing unused/useless functions.
In K we dealt very good with big changes between major releases, by having migration guides in the dokuwiki. There were not many complains about syntax changes.
So if the decision is to go for "." in string concatenation expressions, let's stick only to it. Same for other cases, provide onlye one (and good) option. Anyhow will be a big update, and in this case everyone does testing.
Cheers, Daniel