Literate programming is the art of writing computer programs with the primary goal of human readability.
CWEB–Donald Knuth’s favorite programming language.
FWEB is a scientific-programming-oriented literate programming system for C, C++, and Fortran.
noweb is a simple, language-independent literate programming system. It is packed with an Emacs mode.
It is interesting to note that Perl has native support for literate programming via POD (Plain Old Documentation).