re2c is a preprocessor that generates C-based recognizers from regular
expressions. The input to re2c consists of C/C++ source interleaved
with comments of the form /*!re2c ... */ which contain scanner
specifications. In the output these comments are replaced with code
that, when executed, will find the next input token and then execute
some user-supplied token-specific code.
re2c generates parsers which are not table-based, and can be twice as
fast as flex.