Documentation

Convert a bare interpreter for eff, which (potentially) uses Stop to signal errors, into an interpreter for Resumable. Beware: This will display unsound behaviour if: * the interpreter is wrapped with actions of another effect, as in:

  interpretEff :: InterpreterFor Eff r
  ...

  interpretEffResumable :: InterpreterFor (Resumable Text Eff) r
  interpretEffResumable sem =
  resumable (interpretEff (sem finally releaseResources))
  

In this case, releaseResources will be called after every use of Eff in sem, not after the entire thunk.

• the interpreter of a higher-order effect uses a different interpreter after using runT/bindT. In this case, it will use the original interpreter instead.

If your use case matches one of these conditions, you'll need to use interpretResumable.

>>> run $ resumable interpretStopper (interpretResumer mainProgram)
237

Convenience combinator for turning an interpreter that doesn't use Stop into a Resumable.

Like resumable, but use exceptions instead of ExceptT.

Like interpretResumable, but for higher-order effects.

Create an interpreter for Resumable err eff by supplying a handler function for eff, analogous to interpret. If the handler throws errors with Stop, they will be absorbed into Resumable, to be caught by resume in a downstream interpreter.

interpretStopperResumable ::
  Member (Stop Boom) r =>
  InterpreterFor Stopper r
interpretStopperResumable =
  interpretResumable \case
    StopBang -> stop (Bang 13)
    StopBoom -> stop (Boom "ouch")

>>> run $ interpretStopperResumable (interpretResumer mainProgram)
237

Convert an interpreter for eff that uses Error into one using Stop and wrap it using resumable.

Convert an interpreter for eff that throws errors of type err into a Resumable, but limiting the errors handled by consumers to the type handled, which rethrowing Errors of type unhandled.

The function canHandle determines how the errors are split.

newtype Blip =
  Blip { unBlip :: Int }
  deriving (Eq, Show)

bangOnly :: Boom -> Either Text Blip
bangOnly = \case
  Bang n -> Right (Blip n)
  Boom msg -> Left msg

interpretResumerPartial ::
  Member (Resumable Blip Stopper) r =>
  InterpreterFor Resumer r
interpretResumerPartial =
  interpret \ MainProgram ->
    resume (192 <$ stopBang) \ (Blip num) ->
      pure (num * 3)

>>> runError (resumableFor bangOnly interpretStopper (interpretResumerPartial mainProgram))
Right 39

Variant of resumableOr that uses Maybe and rethrows the original error.

Reinterpreting variant of resumableFor.

Interpret an effect eff by wrapping it in Resumable and Stop and leaving the rest up to the user.