





A whirlwind tour through classic text adventure games, interpreters, SMT solvers, and monad transformer stacks, to answer the eternal question of mankind: "Can you get the coin into the throne room, if it is behind a locked door, and the key is guarded by a vampire?" Gergő Érdi once managed to put "Practical Theorist" as his job title on a business card. He arrived at typed functional programming from looking for ways to restrict APIs to expose just the right degrees of freedom. His claim to fame is adding pattern synonyms to GHC. These days, he's writing a book about creating retrocomputers on FPGAs using the Haskell dialect, Clash.