bluefin-internal 0.0.4.0 → 0.0.4.2

raw patch · 4 files changed

+68/−1 lines, 4 filesPVP: minor bump suggested

API additions: PVP suggests at least a minor version bump

API changes (from Hackage documentation)

Files

• CHANGELOG.md +4/−0
• bluefin-internal.cabal +1/−1
• src/Bluefin/Internal.hs +42/−0
• src/Bluefin/Internal/Examples.hs +21/−0

@@ -1,3 +1,7 @@+## 0.0.4.2++* Add documentation for `Handle`+ ## 0.0.4.0  * Add functions for compound effects

@@ -1,6 +1,6 @@ cabal-version:      3.0 name:               bluefin-internal-version:            0.0.4.0+version:            0.0.4.2 license:            MIT license-file:       LICENSE author:             Tom Ellis

@@ -199,7 +199,46 @@ -- @()@ and then yields values of type @a@. type Stream a = Coroutine a () +-- | You can define a @Handle@ instance for your compound handles.  As+-- an example, an "application" handle with a dynamic effect for+-- database queries, a concrete effect for application state and a+-- concrete effect for a logging effect might look like this:+--+-- @+-- data Application e = MkApplication+--   { queryDatabase :: String -> Int -> Eff e [String],+--     applicationState :: State (Int, Bool) e,+--     logger :: Stream String e+--   }+-- @+--+-- To define @mapHandle@ for @Application@ you should apply+-- @mapHandle@ to all the fields that are themeselevs handles and+-- apply @useImpl@ to all the fields that are dynamic effects:+--+-- @+-- instance Handle Application where+--   mapHandle+--     MkApplication+--       { queryDatabase = q,+--         applicationState = a,+--         logger = l+--       } =+--       MkApplication+--         { queryDatabase = (fmap . fmap) useImpl q,+--           applicationState = mapHandle a,+--           logger = mapHandle l+--         }+-- @+--+-- Note that preceding @useImpl@ on the dynamic effect there is one+-- fmap per @->@ that appears in type of the dynamic effect.  That is,+-- @queryDatabase@ has type @String -> Int -> Eff e [String]@, which+-- has two @->@, so there are two @fmap@s before @useImpl@.+ class Handle (h :: Effects -> Type) where+  -- | Used to create compound effects, i.e. handles that contain+  -- other handles.   mapHandle :: (e :> es) => h e -> h es  instance Handle (State s) where@@ -914,6 +953,9 @@ tell (Writer y) = yield y  newtype Reader r (e :: Effects) = MkReader r++instance Handle (Reader r) where+  mapHandle (MkReader r) = MkReader r  runReader ::   -- | ͘

@@ -576,3 +576,24 @@ -- Left "/tmp/doesn't exist: openFile: does not exist (No such file or directory)" -- \$ cat /tmp/bluefin -- Hello!++-- instance Handle example++data Application e = MkApplication+  { queryDatabase :: String -> Int -> Eff e [String],+    applicationState :: State (Int, Bool) e,+    logger :: Stream String e+  }++instance Handle Application where+  mapHandle+    MkApplication+      { queryDatabase = q,+        applicationState = a,+        logger = l+      } =+      MkApplication+        { queryDatabase = (fmap . fmap) useImpl q,+          applicationState = mapHandle a,+          logger = mapHandle l+        }