A-non-blocking-lexing-toolkit-for-Scala is a project mainly written in Scala, it's free.
A non-blocking lexing toolkit for Scala in less than 800 lines of code, from regex derivatives
A non-blocking lexing toolkit for Scala in less than 800 lines of code, from regex derivatives by Matt Might.
http://matt.might.net/articles/nonblocking-lexing-toolkit-based-on-regex-derivatives/