The structure of an FWEB file

• Divided into sections . Each section comprises:
  • the TEX part: a general explanation for the following code fragment;
  • the definition part: in which various macros used by the following code fragment may be introduced;
  • the code itself.
• With the help of the sections a huge and complex code may be partitioned into small code fragments, each of which is simple to understand.
• Sections can be combined into modules, and modules can be combined into whole programs:

  There is no need for sections that must be physically contiguous in the output file to be contiguous in the source file. This allows for great flexibility in structuring the documentation of the code.

• A code should neither be undercommented nor overcommented. Our example above is a bad one in this respect, because the comments in it state the obvious.