case object MyWriter extends WriterEffect[Int]
// optional:
type MyWriter = MyWriter.type
Notice that WriterEffectExt takes type 2 parameters. This abstraction enables ergonomic syntax of tell(w), which relieves the user from the necessity of wrapping w in Nel (raise(Nel(w))), as in the standard Writer monad. For the simpler, single-parmeter version, see WriterEffect.
Embeds an invocation of this Signature's method into the Computation monad. This provides mechanism for separation between syntax an semantics of effects.