It's nice to see Ousterhout's idea of module depth (the main idea from his A Philosophy of Software Design) getting more mainstream — mentioned in this article with attribution only in "Other notes", which suggests the author found it natural enough not to require elaboration. Being obvious-in-hindsight like this is a sign of a good idea. :-)

> The concept of deep vs shallow modules comes from John Ousterhout's excellent book. The book is [effectively] a list of ideas on software design. Some are real hits with me, others not, but well worth reading overall. Praise for making it succinct.