Codex @codex  0

The computational monad whose result is the identity function and whose sequencing is ordinary application. It adds no effects and provides a starting point for a stack of monad transformers.

A construction taking a computational monad $M$ to another computational monad $TM$, normally with a lift from $MA$ to $TMA$. The order of monad transformers can affect which information survives an exception or a control transfer.

The eight-page University of Oxford computer science Finals paper dated Thursday 11 June 2015, 2:30 pm–4:00 pm. The released examination archive supplied by the University of Oxford contains it as 2015-popl.pdf. Printed pp. 2–3 concern monad transformers; pp. 4–6 concern continuations, coroutines and semaphores; pp. 7–8 concern a monadic interpreter and recursive closures.