From 7a0cb8f36273e581a0220383dd39fd619c6c57bc Mon Sep 17 00:00:00 2001
From: Athan Clark <athan.clark@gmail.com>
Date: Tue, 28 Aug 2018 14:52:12 -0600
Subject: [PATCH] generic instance for buffers

---
 bower.json           |  2 ++
 src/Node/Buffer.purs | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/bower.json b/bower.json
index 60c7536..53756c3 100644
--- a/bower.json
+++ b/bower.json
@@ -14,11 +14,13 @@
   },
   "dependencies": {
     "purescript-eff": "^3.0.0",
+    "purescript-generics": "^4.0.0",
     "purescript-maybe": "^3.0.0"
   },
   "devDependencies": {
     "purescript-assert": "^3.0.0",
     "purescript-console": "^3.0.0",
+    "purescript-psci-support": "^3.0.0",
     "purescript-foldable-traversable": "^3.0.0"
   }
 }
diff --git a/src/Node/Buffer.purs b/src/Node/Buffer.purs
index 0a5f7dd..c5b4729 100644
--- a/src/Node/Buffer.purs
+++ b/src/Node/Buffer.purs
@@ -24,7 +24,11 @@ module Node.Buffer
 
 import Prelude
 import Control.Monad.Eff (Eff, kind Effect)
+import Control.Monad.Eff.Unsafe (unsafePerformEff)
 import Data.Maybe (Maybe(..))
+import Data.Generic (class Generic, toSpine, fromSpine, GenericSignature (SigProd), GenericSpine (SProd))
+import Data.Array as Array
+import Type.Proxy (Proxy (..))
 import Node.Encoding (Encoding, encodingToNode)
 
 -- | Type synonym indicating the value should be an octet (0-255). If the value
@@ -37,6 +41,19 @@ type Offset = Int
 -- | An instance of Node's Buffer class.
 foreign import data Buffer :: Type
 
+instance genericBuffer :: Generic Buffer where
+  toSpine x = SProd "Node.Buffer.Buffer" [\_ -> toSpine $ unsafePerformEff $ toArray x]
+  toSignature Proxy = SigProd "Node.Buffer.Buffer" [{sigConstructor: "Node.Buffer.Buffer", sigValues: []}]
+  fromSpine s = case s of
+    SProd d xs
+      | d == "Node.Buffer.Buffer" -> case Array.head xs of
+        Just y -> case fromSpine (y unit) of
+          Just xs' -> Just $ unsafePerformEff $ fromArray xs'
+          _ -> Nothing
+        _ -> Nothing
+      | otherwise -> Nothing
+    _ -> Nothing
+
 instance showBuffer :: Show Buffer where
   show = showImpl