Add FromField Integer

lib/Database/PostgreSQL/Opium/FromField.hs

@@ -41,22 +41,28 @@ class FromField a where
 
 -- | See https://www.postgresql.org/docs/current/datatype-character.html.
 instance FromField Text where
-  validOid _ = Oid.text \/ Oid.character \/ Oid.characterVarying
+  validOid Proxy = Oid.text \/ Oid.character \/ Oid.characterVarying
   parseField = takeText
 
 -- | See https://www.postgresql.org/docs/current/datatype-character.html.
 instance FromField String where
-  validOid _ = validOid @Text Proxy
+  validOid Proxy = validOid @Text Proxy
   parseField = Text.unpack <$> parseField
 
 -- | See https://www.postgresql.org/docs/current/datatype-character.html.
 -- This instance accepts all character types but fails to decode fields that are not exactly one character.
 instance FromField Char where
-  validOid _ = validOid @Text Proxy
+  validOid Proxy = validOid @Text Proxy
   parseField = anyChar
 
+-- | See https://www.postgresql.org/docs/current/datatype-numeric.html.
 instance FromField Int where
-  validOid _ = Oid.smallint \/ Oid.integer \/ Oid.bigint
+  validOid Proxy = Oid.smallint \/ Oid.integer \/ Oid.bigint
+  parseField = signed decimal
+
+-- | See https://www.postgresql.org/docs/current/datatype-numeric.html.
+instance FromField Integer where
+  validOid Proxy = Oid.smallint \/ Oid.integer \/ Oid.bigint
   parseField = signed decimal
 
 doubleParser :: Parser Double
@@ -70,11 +76,11 @@ doubleParser = choice
     infinity = 1 / 0
 
 instance FromField Float where
-  validOid _ = Oid.real
+  validOid Proxy = Oid.real
   parseField = fmap double2Float doubleParser
 
 instance FromField Double where
-  validOid _ = Oid.real \/ Oid.doublePrecision
+  validOid Proxy = Oid.real \/ Oid.doublePrecision
   parseField = doubleParser
 
 boolParser :: Parser Bool
@@ -85,5 +91,5 @@ boolParser = choice
 
 -- | See https://www.postgresql.org/docs/current/datatype-boolean.html.
 instance FromField Bool where
-  validOid _ = Oid.boolean
+  validOid Proxy = Oid.boolean
   parseField = boolParser