Resolve #852: Export ifromJSON and iparse from Data.Aeson.Types. Add iparseEither.

Author: phadej

changelog.md

@@ -6,6 +6,7 @@ For the latest version of this document, please see [https://github.com/haskell/
 - Change `KeyValue` instances to be more general (and use equality to constraint them) instead of being more lax flexible instances.
 - Export `Key` type also from `Data.Aeson.KeyMap` module.
 - Export `mapWithKey` from `Data.Aeson.KeyMap` module.
+- Export `ifromJSON` and `iparse` from `Data.Aeson.Types`. Add `iparseEither`.
 
 ### 2.0.3.0
 

src/Data/Aeson/Types.hs

@@ -29,6 +29,7 @@ module Data.Aeson.Types
     , typeMismatch
     , unexpected
     -- * Type conversion
+    -- ** Parsing
     , Parser
     , Result(..)
     , FromJSON(..)
@@ -37,12 +38,19 @@ module Data.Aeson.Types
     , parseEither
     , parseMaybe
     , parseFail
-    , ToJSON(..)
-    , KeyValue(..)
+    -- ** Parser error handling
     , modifyFailure
     , prependFailure
     , parserThrowError
     , parserCatchError
+    -- ** Parsing with paths
+    , IResult (..)
+    , ifromJSON
+    , iparse
+    , iparseEither
+    -- ** Encoding
+    , ToJSON(..)
+    , KeyValue(..)
 
     -- ** Keys for maps
     , ToJSONKey(..)

src/Data/Aeson/Types/Internal.hs

@@ -43,6 +43,7 @@ module Data.Aeson.Types.Internal
     , JSONPathElement(..)
     , JSONPath
     , iparse
+    , iparseEither
     , parse
     , parseEither
     , parseMaybe
@@ -580,6 +581,14 @@ parseEither m v = runParser (m v) [] onError Right
   where onError path msg = Left (formatError path msg)
 {-# INLINE parseEither #-}
 
+-- | Run a 'Parser' with an 'Either' result type.
+-- If the parse fails, the 'Left' payload will contain an error message and a json path to failed element.
+--
+-- @since 2.1.0.0
+iparseEither :: (a -> Parser b) -> a -> Either (JSONPath, String) b
+iparseEither m v = runParser (m v) [] (\path msg -> Left (path, msg)) Right
+{-# INLINE iparseEither #-}
+
 -- | Annotate an error message with a
 -- <http://goessner.net/articles/JsonPath/ JSONPath> error location.
 formatError :: JSONPath -> String -> String