A structured modular program is a collection of units with identifying names: Functions, subroutines, procedures, variables, objects, classes, ...

* What makes a good program unit?
* What is the best way to order the units?

Arthur Koestler: Holons

Nature handles its complexity in a structure of holons, items that are both a whole and a part. Each level has its own rules.

Chuck Moore: Words

Program elements are words defined by words. Words are holons.

Donald Knuth: Literate

A program is a text to be read by humans and converted to code to be executed ('read') by machines. Knuth was inspired by Koestler. A literate program is written like a story as a collection of units, each containing code and text (comments).

HolonForth: Book

The program is handled in a browser like a book with chapters (files), sections (classes, components), and units (functions, routines, objects, methods, words).