The Howdy Glossary

Ratfor, short for Rational Fortran, is a preprocessor developed by Brian Kernighan at Bell Laboratories in the late 1970s. It enables programmers to code in an extended version of Fortran resembling C, making it easier for new programmers to transition and offering features like if-else constructs and loops absent from standard Fortran. Once preprocessed, Ratfor code can be compiled without modification by standard Fortran compilers.

Ratfor's structure incorporates features such as if-else constructs, do-while loops, and complex expressions with parentheses—elements borrowed from languages like C that were either limited or absent in standard Fortran syntax. These structured programming elements enhanced the expressiveness and ease of use for programmers, bridging the gap between the imperative style of C and the numerical computing power of Fortran. This combination made Ratfor a valuable tool for developers seeking a more versatile and modern programming experience within the Fortran ecosystem.

During its peak usage period in the late 1970s and 1980s, Ratfor faced competition from evolving versions of traditional Fortran and emerging languages like C and Pascal that also offered structured programming features. Despite these competitors, Ratfor's unique blend of C-like syntax with computational prowess allowed it to carve out a niche in the programming landscape. Its capability to preprocess code into standard Fortran format ensured seamless integration with existing development environments while maintaining compatibility with any compatible Fortran compiler. This versatility positioned Ratfor as an appealing tool for both new programmers transitioning into scientific fields reliant on Fortran and experienced developers seeking enhanced readability and functionality in their code.