Build-your-own-[grep, Redis] in Haskell

"How can one write a 'real' application in Haskell" is a common question by students after completing a functional programming course.
Following the 'build-your-own-x' concept, we provide two partial, but fully working implementations of the grep and Redis applications in Haskell.

The principle of algebra-driven design, also known as denotational design, is closely followed for these implementations.
Both code bases are accompanied with detailed and reviewed explanations which serve as a tutorial for experienced software engineers and students alike.

All code, along with the explanations are released open-source and, in addition, are used at OST as part of the functional programming lecture.