github/semantic
1
1
Fork 0
mirror of https://github.com/github/semantic.git synced 2025-01-03 04:51:57 +03:00
Code Issues Projects Releases Wiki Activity

📝 the MonadNonDet instance for NonDetEff.

Browse Source
This commit is contained in:
Rob Rix 2017-12-21 11:14:31 -05:00
parent 1758195761
commit 9390869304
1 changed files with 1 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/Control/Monad/Effect/NonDet.hs
View File

@ -16,6 +16,7 @@ class (Alternative m, Monad m) => MonadNonDet m where
-> m a -- ^ The computation to run locally-nondeterministically.
-> m b -- ^ A _deterministic_ computation producing the 'Monoid'al accumulation of the _locally-nondeterministic_ result values.
-- | Effect stacks containing 'NonDetEff' offer a 'MonadNonDet' instance which implements 'collect' by interpreting the requests for nondeterminism locally, without removing 'NonDetEff' from the stack—i.e. the _capacity_ for nondeterminism is still present in the effect stack, but any local nondeterminism has been applied.
instance (NonDetEff :< fs) => MonadNonDet (Eff fs) where
collect f = interpose (pure . f) (\ m k -> case m of
MZero -> pure mempty