From 9e684170a17696f7273225e9f1bfb73b26309024 Mon Sep 17 00:00:00 2001
From: Nikita Volkov <nikita.y.volkov@mail.ru>
Date: Tue, 10 Nov 2015 17:53:14 +0300
Subject: [PATCH] Enum

---
 hasql.cabal                      |  2 +-
 library/Hasql/Deserialization.hs |  8 ++++++++
 library/Hasql/Serialization.hs   | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/hasql.cabal b/hasql.cabal
index 94e69ed..423e3ec 100644
--- a/hasql.cabal
+++ b/hasql.cabal
@@ -68,7 +68,7 @@ library
     -- parsing:
     attoparsec >= 0.10 && < 0.14,
     -- database:
-    postgresql-binary >= 0.7.2 && < 0.8,
+    postgresql-binary >= 0.7.3 && < 0.8,
     postgresql-libpq == 0.9.*,
     -- data:
     dlist >= 0.7 && < 0.8,
diff --git a/library/Hasql/Deserialization.hs b/library/Hasql/Deserialization.hs
index 4be5c64..9de2b2d 100644
--- a/library/Hasql/Deserialization.hs
+++ b/library/Hasql/Deserialization.hs
@@ -45,6 +45,7 @@ module Hasql.Deserialization
   array,
   composite,
   hstore,
+  enum,
   -- * Array
   Array,
   arrayDimension,
@@ -525,6 +526,13 @@ hstore :: (forall m. Monad m => Int -> m (Text, Maybe Text) -> m a) -> Value a
 hstore replicateM =
   Value (Value.decoder (const (Decoder.hstore replicateM Decoder.text_strict Decoder.text_strict)))
 
+-- |
+-- Given a partial mapping from text to value,
+-- produces a deserializer of that value.
+enum :: (Text -> Maybe a) -> Value a
+enum mapping =
+  Value (Value.decoder (const (Decoder.enum mapping)))
+
 
 -- ** Instances
 -------------------------
diff --git a/library/Hasql/Serialization.hs b/library/Hasql/Serialization.hs
index 48bab63..b61cfcc 100644
--- a/library/Hasql/Serialization.hs
+++ b/library/Hasql/Serialization.hs
@@ -25,6 +25,7 @@ module Hasql.Serialization
   uuid,
   json,
   array,
+  enum,
   -- * Array
   Array,
   arrayValue,
@@ -220,6 +221,15 @@ array (Array imp) =
   Array.run imp & \(arrayOID, encoder') ->
     Value (Value.Value arrayOID arrayOID encoder')
 
+-- |
+-- Given a function,
+-- which maps the value into the textual enum label from the DB side,
+-- produces a serializer of that value.
+{-# INLINABLE enum #-}
+enum :: (a -> Text) -> Value a
+enum mapping =
+  Value (Value.unsafePTI PTI.text (const (Encoder.enum mapping)))
+
 
 -- ** Instances
 -------------------------