I wonder how Qt has evolved into a universal structure that forces the programmer who uses it, believes that everything that is useful should start with the letter Q. Very dot-netty. Qt is just a class library that runs on top of the language, and this does not preclude the use of regular libraries that do the work. Especially when a library that has little to do with the presentation of the user interface is the job that Qt does so well.
There are many libraries that provide lexical analysis and parsing. It starts with Lex and Yacc, Flex and Bison next, etc. You only need to enable Qt for error messages, they readily support this.