from

• sltc.hs

  • https://github.com/branebb/simply-typed-lambda-calculus/blob/main/STLC.hs

• sltc2.hs

  • https://www.philipzucker.com/extra-simple-simply-typed-lambda-calculus-haskell/

https://www.cs.umd.edu/class/fall2017/cmsc631/cmsc631-hws/plf/Stlc.html

https://www.thev.net/PaulLiu/representing-STLC.html

https://crypto.stanford.edu/~blynn/lambda/simply.html

https://github.com/archanpatkar/styla