Is a parser very slow?

Hello, the problem here is that by using something like "{AllMacro}*" in your LookBehind, you are effectively telling the lexer to fully go to the beginning of the document on every character.  You probably want to limit ths to a single line look behind (everything except \n) or some other delimiter.

I assume that you also have some explicit patterns that are defined within the group?  But regardless, that sort of look-behind will slow things down.

A better way might be to change it so if you see a ".option", then you enter a new lexical state.  So make it a start scope.  And in that other lexical state, color your identifiers differently in the proper scenarios.  Then exit at the line terminator (\n) or equals (=).