Literate Programming in Forth

We look at Donald Knuth's concept of \Literate Programming," investigating exactly what it is and how it is used to assist conventional programmers. We then ask what lessons we can learn from this idea and if it is possible to apply them to Forth. We look at the alterations needed to the system and/or Forth to allow us to take advantage of this system. Indeed do we obtain all of the advantages that Knuth claims. Finally some examples of Forth coding techniques are given allowing us to compare the more traditional techniques with Knuth's system. 1 What is Literate Programming Literate programming was created by Donald Knuth during the development of his TEX typesetting system. It is the combination of documentation and source together in a fashion suited for reading by human beings. In general, literate programs combine source and documentation in a single le, referred to as a WEB. Literate programming tools then parse the le to produce either readable documentation or compilable source. All the original work revolves around a particular literate programming tool called WEB. Knuth says [Knu92]: The philosophy behind WEB is that an experienced system programmer, who wants to provide the best possible documentation of his or her software products, needs two things simultaneously: a language like TEX for formatting, and a language like C for programming. Neither type of language can provide the best documentation by itself; but when both are appropriately combined, we obtain a system that is much more useful than either language separately. The structure of a software program may be thought of as a web that is made up of many interconnected pieces. To docu-