[feature] finallyDo

[ni-ko-o-kin]

import ConcurrentTask as CT exposing (ConcurrentTask)

finallyDo : ConcurrentTask e a -> ConcurrentTask e b -> ConcurrentTask e a
finallyDo secondTask firstTask =
    firstTask
        |> CT.onError (\e -> secondTask |> CT.andThenDo (CT.fail e))
        |> CT.andThenDo secondTask

Similar to Javascripts try-catch-finally statement. For example, I'm using finallyDo to make sure unlockResource gets called in both, the success and failure case:

callInsideLock : ConcurrentTask e a -> ConcurrentTask e b
callInsideLock task =
    lockResource
        |> CT.andThenDo task
        |> CT.finallyDo unlockResource

instead of

callInsideLock : ConcurrentTask e a -> ConcurrentTask e b
callInsideLock task =
     lockResource
        |> CT.andThenDo (task |> CT.onError (\e -> CT.andThenDo (CT.fail e) unlockResource))
        |> CT.andThenDo unlockResource

Are you interested in adding this to elm-concurrent-task? I would open a PR if so.

[andrewMacmurray]

Sorry missed this - sure, that feels like it would fit sensibly in the helpers section, feel free to make a PR.

[ni-ko-o-kin]

Thanks! WIP!

[ni-ko-o-kin]

see #34