In preparation for a talk, I updated Knuth's original diagram in Donald E. Knuth. Literate programming. The Computer Journal, 27(2):97–111, May 1984. The new diagram is Sweave specific. Click the Sweave diagram for a PDF version, or right-click and select 'save image as' for the PNG version. Permission is granted for any use of the Sweave diagram.

Sweave Diagram

Knuth's (1984) Original