Here is a list of functional programs applied to real-world tasks. The main criterion for being real-world is that the program was written primarily to perform some task, not primarily to experiment with functional programming.
Related
Lambda Associates
lambdassociates.org · · Page
Structure and Interpretation of computer programs
mitpress.mit.edu · · Page
Refactoring Ruby with Monads
codon.com · · Page
When I say "Monads aren't difficult, and you are smart enough to understand them," I'm now going to link to
CS240h: Functional Systems in Haskell
scs.stanford.edu · · Page
CS240h: Functional Systems in Haskell #haskell #systems #programming #functional
Python vs Haskell : An unsatisfying exercise in comparative code linguistics
sandersn.com · · Page
ongoing · Concur.next — The Laundry List
tbray.org · · Page