AFSL (Almost Formal Specification Language) is a small and
  configurable algebraic language designed for studying the process
  of formalization. We give an overview of its most distinctive
  aspects. In particular we highlight the mechanism for combining
  different function features (such as partiality, side-effects,
  non-determinism, etc.) in a uniform and extendible way. The semantics
  of this mechanism is based on monads and the newly introduced concept
  of computational lifting (which will be discussed in Pietro's talk).