Haskell quicksort isn't quicksort, it's an illustration of quicksort. It's not an in-place constant-memory implementation. See also the Haskell Sieve of Eratos

Haskell quicksort isn't quicksort, it's an illustration of quicksort. It's not an in-place constant-memory implementation. See also the Haskell Sieve of Eratosthenes, which isn't a Sieve of Eratosthenes, and is in fact even slower than naive trial division: https://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf https://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf