Add bracket

with minor edits by @tomjaguarpaw

bluefin-internal/src/Bluefin/Internal.hs

@@ -390,6 +390,19 @@ catch ::
   Eff es a
 catch f h = handle h f
 
+-- | @bracket acquire release body@: @acquire@ a resource, perform the
+-- @body@ with it, and @release@ the resource even if @body@ threw an
+-- exception.  This is essentially the same as
+-- @Control.Exception.'Control.Exception.bracket'@, whose
+-- documentation you can inspect for further details.
+bracket ::
+  Eff es a ->
+  (a -> Eff es ()) ->
+  (a -> Eff es b) ->
+  Eff es b
+bracket before after body = UnsafeMkEff $ Control.Exception.bracket
+  (unsafeUnEff before) (unsafeUnEff . after) (unsafeUnEff . body)
+
 -- |
 -- @
 -- >>> runPureEff $ runState 10 $ \\st -> do

bluefin/src/Bluefin/Eff.hs

@@ -4,6 +4,8 @@ module Bluefin.Eff
     -- * Run an 'Eff'
     runPureEff,
     runEff,
+    -- * Resource management
+    bracket,
     -- * Type classes
 
     -- | See "Bluefin.Eff.IO" for the most direct way of doing I/O in