Been doing some reading about lexers and parsers in PHP. Some useful resources:
- https://nitschinger.at/Writing-a-simple-lexer-in-PHP/
- https://www.codediesel.com/php/building-a-simple-parser-and-lexer-in-php/
- https://github.com/weltling/parle/blob/master/README.md
- https://jwage.com/posts/2012/09/15/writing-a-parser-in-php-with-the-help-of-doctrine/
- https://vierbergenlars.wordpress.com/2013/08/09/creating-a-parser-in-php/