[Haskell-beginners] minimal Haskell concepts subset

[Stephen Tetley]

There are a number of languages called "Mini Haskell" that will come
up if you're lucky in a web search.

One from Konstantin Läufer includes type classes, whereas the others
seem to be just small, lazy functional languages.

I think the Haskell history paper presented at HOPL considers type
classes to be the defining feature or Haskell.