From c4807709c4eb505956960f66977baeed2d63d75c Mon Sep 17 00:00:00 2001
From: Alp Mestanogullari <alpmestan@gmail.com>
Date: Fri, 31 Oct 2014 15:40:56 +0100
Subject: [PATCH] add a lot of FromText/ToText instances

---
 src/Servant/Utils/Text.hs | 85 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 80 insertions(+), 5 deletions(-)

diff --git a/src/Servant/Utils/Text.hs b/src/Servant/Utils/Text.hs
index 907627e2..907eb0a3 100644
--- a/src/Servant/Utils/Text.hs
+++ b/src/Servant/Utils/Text.hs
@@ -4,30 +4,31 @@
 module Servant.Utils.Text where
 
 import Data.String.Conversions
+import Data.Int
 import Data.Text
-import Text.Read
+import Data.Text.Read
+import Data.Word
 
+-- | For getting values from url captures, get parameters
 class FromText a where
   fromText :: Text -> Maybe a
 
+-- | For putting values in paths, get parameters
 class ToText a where
   toText :: a -> Text
 
-
 instance FromText Text where
   fromText = Just
 
 instance ToText Text where
   toText = id
 
-
 instance FromText String where
   fromText = Just . cs
 
 instance ToText String where
   toText = cs
 
-
 instance FromText Bool where
   fromText "true"  = Just True
   fromText "false" = Just False
@@ -37,9 +38,83 @@ instance ToText Bool where
   toText True  = "true"
   toText False = "false"
 
+instance FromText Int where
+  fromText = runReader (signed decimal)
+
+instance ToText Int where
+  toText = cs . show
+
+instance FromText Int8 where
+  fromText = runReader (signed decimal)
+
+instance ToText Int8 where
+  toText = cs . show
+
+instance FromText Int16 where
+  fromText = runReader (signed decimal)
+
+instance ToText Int16 where
+  toText = cs . show
+
+instance FromText Int32 where
+  fromText = runReader (signed decimal)
+
+instance ToText Int32 where
+  toText = cs . show
+
+instance FromText Int64 where
+  fromText = runReader (signed decimal)
+
+instance ToText Int64 where
+  toText = cs . show
+
+instance FromText Word where
+  fromText = runReader decimal
+
+instance ToText Word where
+  toText = cs . show
+
+instance FromText Word8 where
+  fromText = runReader decimal
+
+instance ToText Word8 where
+  toText = cs . show
+
+instance FromText Word16 where
+  fromText = runReader decimal
+
+instance ToText Word16 where
+  toText = cs . show
+
+instance FromText Word32 where
+  fromText = runReader decimal
+
+instance ToText Word32 where
+  toText = cs . show
+
+instance FromText Word64 where
+  fromText = runReader decimal
+
+instance ToText Word64 where
+  toText = cs . show
 
 instance FromText Integer where
-  fromText = readMaybe . cs
+  fromText = runReader decimal
 
 instance ToText Integer where
   toText = cs . show
+
+instance FromText Double where
+  fromText = runReader rational
+
+instance ToText Double where
+  toText = cs . show
+
+instance FromText Float where
+  fromText = runReader rational
+
+instance ToText Float where
+  toText = cs . show
+
+runReader :: Reader a -> Text -> Maybe a
+runReader reader t = either (const Nothing) (Just . fst) $ reader t