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Ratfor (short for Rational Fortran) is a programming language implemented as a preprocessor for Fortran 66. It provides modern control structures, unavailable in Fortran 66, to replace and statement numbers.
For example, the following code
max = a
} else {
max = b
}
IF(.NOT.(A.GT.B))GOTO 1
MAX = A
GOTO 2
1 CONTINUE
MAX = B
2 CONTINUE
In 1977, at Purdue University, an improved version of the Ratfor preprocessor was written. It was called Mouse4, as it was smaller and faster than Ratfor. 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." (CSD-TR236).
In comparison to the Ratfor preprocessor on a program of 3000 source lines running on a CDC 6500 system took 185.470 CPU seconds. That was cut by 50% when binary search was used in the Ratfor code. Rewriting the ad hoc lexical scanner using a standard method based on finite automata reduced run time to 12.723 seconds.
With the availability of Fortran 77, a successor named Ratfiv (Ratfor=rat4 => rat5=Ratfiv) could, with an option /f77, output a more readable Fortran 77 code:
IF (A .GT. B) THEN
MAX = A
ELSE
MAX = B
ENDIF
Initial Ratfor source code was ported to C in 1985 and improved to produce Fortran 77 code too. A git tree has been set in 2010 in order to revive ratfor . Although the GNU C compiler had the ability to directly compile a Ratfor file (.r) without keeping a useless intermediate Fortran code (.f) (gcc foo.r), this functionality was lost in version 4 during the move in 2005 from f77 to GNU Fortran.
The original source was available in .deb and .rpm forms at its original site, mirror.corbina.net/mandriva/, and its archive, www.dgate.org/ratfor/ are gone as of April, 2024.
The name of the language is a pun ( Ratfor (RATional FORtran) -> "Rat Four" -> "Rat Five" -> RatFiv).
Ratfiv was developed by Bill Wood at the Institute for Cancer Research, Philadelphia, PA in the early 1980s and released on several DECUS (Digital Equipment Users Group) SIG (Special Interest Group) tapes. It is based on the original Ratfor by Brian 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).
Ratfiv V2.1 was distributed on the DECUS RSX82a SIG tape. Ratfiv V2.1 archive
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