Initial explanation
初步解释
I am trying to do some testing with a custom regular expression engine but I got tired of writing the NFAs out by hand so I tried to make a parser with little success. Usually when people parse a regex, they create multiple intermediate structures that are eventually converted into the final machine. For my simple NFA definition, I believe the parsing could actually be done in one pass, though I have not yet determined either (a) why it actually can't or (b) how to do it, though my parser can parse very simple statements.I am trying to do
