Data Validation inspired by JSR305

This library is designed for validate haskell records, such as in configurations or web request parameters.

Usage:

{-# LANGUAGE RecordWildCards #-}
module Main where
import Data.Menshen
data Body = Body
  { name :: String
  , age  :: Int
  } deriving Show

verifyBody :: Validator Body
verifyBody = vcvt $ \Body{..} -> Body
  <$> name ?: mark "name" . pattern "^[a-z]{3,6}$"
  <*> age  ?: mark "age"  . minInt 1 . maxInt 150

makeBody :: String -> Int -> Either String Body
makeBody name age = Body{..} ?: verifyBody

main = do
  print $ makeBody "daniel" 15

Useage in Record parsing process:

instance HasValid Parser where
  invalid = fail . toI18n

instance FromJSON Body where
  parseJSON = withObject "Body" $ \v -> Body
    <$> v .: "name" ? pattern "^[a-z]{3,6}$"
    <*> v .: "age"  ? minInt 1 . maxInt 150