> Is this supposed to be a specific coding style or paradigm?

This is indeed Whitney's distinctive coding style, well known for its use in his various array programming language interpreters. His coding style is famously minimalist and idiosyncratic often fitting entire implementations of interpreters in a few pages.

This has been discussed a number of times on HN. I have collected some of the interesting comments on this topic from previous threads here in this meta comment: https://news.ycombinator.com/item?id=45800777#45805346