But it doesn't appear that almost every pretty printer is based on the Wadler algorithm. It seems like MOST of them are not?
e.g. clang-format is one of the biggest and best, and it has a model that includes "unwrapped lines", a "layouter", a line break cost function, exhaustive search with memoization, and Dijikstra's algorithm:
https://llvm.org/devmtg/2013-04/jasper-slides.pdf
The YAPF Python formatter is based on this same algorithm - https://github.com/google/yapf
The Dart formatter used a model of "chunks, rules, and spans" - https://journal.stuffwithstuff.com/2015/09/08/the-hardest-pr...
It almost seems like there are 2 camps -- the functional algorithms for functional/expression-based languages, and other algorithms for more statement-based languages.
Though I guess Prettier/JavaScript falls on the functional side.
I just ran across this paper that includes a nice survey (on lobste.rs) and it seems to cover the functional pretty printing languages influenced by Wadler, in the functional style (e.g. for and in Racket or Haskell), but not the other kind of formatter ("Google" formatters perhaps)