Ratfor provides the following kinds of flow-control statements, described by Kernighan and Plauger as "shamelessly stolen from the language C, developed for the UNIX operating system by D.M.
A published document by Dr. Douglas Comer, professor at Purdue, concluded "contrary to the evidence exhibited by the designer of Ratfor, sequential search is often inadequate for production software.
Furthermore, in the case of lexical analysis, well-known techniques do seem to offer efficiency while retaining the simplicity, ease of coding and modularity of ad hoc methods."
Rewriting the ad hoc lexical scanner using a standard method based on finite automata reduced run time to 12.723 seconds.
It is based on the original Ratfor by B. Kernighan and P. J. Plauger, with rewrites and enhancements by David Hanson and friends (U. of Arizona), Joe Sventek and Debbie Scherrer (Lawrence Berkeley National Laboratory).