It won’t accept a dot because the words are between \b. \b is a word boundary (a zero width representation of where a word [a-zA-Z0-9_]+ begins and ends. This is also why the CSS syntax language will not highlight -moz-border-radius and such. The leading dash cannot be picked up because the word boundary would fall after it. I ended up fixing it for my own personal use.
I am not sure what you are wanting exactly, so I can’t really give advise. Ultimately what exactly are you hoping to highlight. I have done things like this before. I actually modified my python to scope all function calls only after the dot like so.
All function calls that are not built in functions are pink
If you give me a idea of what exactly you are trying to do, maybe I can help some. Some times you have to inject rules before other rules to catch things. I think I made a number of changes until I finally got function calls to highlight proper (without highlighting all parent dot object members and keep built in function names to not highlight when they were dot call functions and not get overridden with my new scope. It was a little tricky.