I guess I should have been more clear in my advice about not using regular expressions: if you have a tool that allows glueing multiple regular expressions toge

I guess I should have been more clear in my advice about not using regular expressions: if you have a tool that allows glueing multiple regular expressions together and erasing the cost of the abstraction (e.g. no allocation of temporary match result objects, substrings, etc) - then certainly that would be a preferred way to code the lexer. Just don't sprinkle a bunch of unconnected `new RegExp()` / `re.exec` around the code and expect that to be reach peak lexing speed.