[s-zeng]

Monads can be thought of as arbitrary function colourings, hence the prior mention of Haskell potentially being a good fit. Of course monads are implementable in almost any other language, but few have as much syntax sugar or general library support as Haskell does, except maybe Ocaml

[jandrese]

Yeah, but how do you design a Monad that does the "tell this other thread to unblock and unwind its state because an external error has triggered? You know, the basic function of an interrupt?

[ratorx]

There’s two separate aspects here:

1) Monads used to restrict the computation available in the context of a signal handler (or function coloring etc, basically a way for a compiler or static checker to determine that a block of code does not call unsafe functions)

2) The actual process of handling a signal received by the signal handler

I think me and the parent are referring to 1). 2) is also important, but it is not a signal specific concern. Even without a signal handler, if you want to write an application which handles async input, you have to handle the case of processing the input to do something useful (eg. let’s say you are writing an HTTP server and want to have a network endpoint for safely killing the thing).

I think the generally recommended way to represent 2) in a pure way is to model the signal as a state machine input and handle it like all other communication.