coeffects can act as interpreters for effects

This is currently more of wish than a true fact. But here are some motivating examples to suggest why this might be the case:

Consider a reader/input effectful computation:

addInput3Times : {input int} int
addInput3Times = !input + !input + !input

one strategy for evaluating this is to provide it with a constant value:

runInputConst : int -> forall a. {input int} a -> a

we can alternatively view this as adjoining the context co-effect and then evaluating via via the adjunction between Product and Reader.

-- given:
context : forall a. int -> a -> [context int] a
eval : forall a. [context int] {input int} a -> a

-- we can do:
eval (context 3 addInput3Times)) = 9