úÎ!_e\õ     © 2018 Luka Had~iegri MIT $Luka Had~iegri <reygoch@gmail.com>  experimental  portable SafeFTV\2 valor0 is basically a function that takes in an input i and returns an error e! wrapped in your monad of choice m.To construct a  you can use functions , , , , ,  and  ". Intended way of constructing a  is by using the  interface.CAbove mentioned functions expect a test (or tests) in the form of x -> ExceptT e m x. l was chosen here because it is a monad transformer and allows ust to throw an error and use a custom monad mÿ. This is useful in case you have to check the database to validate some data or your test relies on success or failure of another field. You can use state monad or transformer to pass in the data being validated so that it is accessible within the test. To run your  against some data you can use   function, or  S if you don't want to use any particular monad and get the pure result wrapped in .?Here is an example of a few simple tests and construction of a  for the previously defined User record:  nonempty' ::  m =>  ->   m  nonempty' t = if  t then throwE "can't be empty" else  t nonempty ::  m =>  ->  [] m  nonempty t = if  t then throwE ["can't be empty"] else  t nonbollocks ::  m =>  ->  [] m + nonbollocks t = if t == "bollocks" then throwE ["can't be bollocks"] else  t nonshort ::  m =>  ->  [] m  nonshort t = if  t < 10 then throwE ["too short"] else  t userValidator ::  m => ) User m UserError userValidator = User   email nonempty'  , username [nonempty, nonbollocks, nonshort] valor-Type that is used to carry the errors within ). It's meant to be used only internally.valor™A simple type level function that is usefull to get rid of the boilerplate in case you want your error and data type to have the same shape / structure.It takes in three arguments: aA type with a kind of * -> *9 that basically serves as a flag which determines if ' will return the error type wrapped in 3 or a value type. To return the error type use " and to return value type use .e'Type that should be used for the error.x'Type that should be used for the value.qHere is an example of how to use it to reduce boilerplate, instead of this (sill perfectly acceptable by Valor): N{ -# LANGUAGE DuplicateRecordFields #- } -- module Test -- import Data.Text ( ' ) -- data User = User { username ::  , password ::  } deriving ( / ) data UserError = UserError { username ::  : -- this field will have only one error , password ::  [6] -- this one can have multiple errors } deriving (  ) ˆwhich can get painful to maintain an repetitive to write if you have a lot of fields in your records, you can just write the following: ™{ -# LANGUAGE FlexibleInstances #- } { -# LANGUAGE StandaloneDeriving #- } { -# LANGUAGE TypeSynonymInstances #- } -- module Test -- import Data.Valor ( ,  ) import Data.Text ( " ) import Data.Functor.Identity ( / (..) ) -- data User' a = User { username ::  a   , password ::  a []  } type User = User'  deriving instance  User type UserError = User'  deriving instance  UserError ¢This approach requires a few language extensions to allow us instance derivation, but it removes a lot of the boilerplate and maintenance costs in the long run. All in all, ž is quite easy to understand, it takes around 5 min to understand this type family even if you've never used type families before , just take a look at the  Equations below:valor A simple "tag" used to tell the 8 type family that we are constructing the "error" type.valorFUse this in case you are not interested in validating a certain field.valor0Runs a single check against the specified field.valor/Runs a single check over every element of some   "container".¹This is quite useful if you for example have a field that contains array of items and you want to run a check against every single element of that list instead of the list as a whole.valorMRuns multiple checks against the specified field. Resulting error must be a !y so that it can be combined or accumulated in some fashion, most convenient thing would be to use a list of "something".valorBasically the same thing as 7 but it allows you to run multiple checks per element.valorRuns a custom made  against the field data. valorRuns a custom made ! against the every element in a   container. valor!This function is used to run the  against the input data i/, once validation process is finished it will  return the error e wrapped in the monad m of your choice. valorQIn case you don't have a need for a monad you can use this function to run your  and get pure  instead of  wrapped in a monad.Here is an example of running  userValidator over some invalid data: AbadUser :: User badUser = User "boaty@mcboatface.com" "bollocks" >>>   userValidator badUser " (User {email = # , username = "% ["can't be bollocks","too short"]}) valor that never returns an errorvalorfield selectorvalor field checkvalor resulting valorfield selectorvalor field checkvalor resulting valorfield selectorvalorlist of field checksvalor resulting valorfield selectorvalorlist of field checksvalor resulting valorfield selectorvalor custom field valor resulting  valorfield selectorvalor custom field valor resulting  valor to run against the input datavalor$input data that you want to validatevalorresult of the validation valor to run against the input datavalor$input data that you want to validatevalorresult of the validation   Safe\Ð$%&'()*+,      !"#$%&'()*+,-./0123456789:;$valor-0.1.0.0-3LuvKpwZTYp4pm6pc4jGTF Data.ValorTextnulllength Data.Text Paths_valor Validator ValidatableValidateskipcheckmapCheckchecks mapChecks subValidatormapSubValidatorvalidate validatePure$fApplicativeValidated$fFunctorValidated$fMonoidValidated$fSemigroupValidated$fApplicativeValidator$fFunctorValidator$fMonoidValidator$fSemigroupValidator$fShowValidatedbaseGHC.Base Applicativetransformers-0.5.5.0Control.Monad.Trans.ExceptExceptTMaybeMonadStringpure Data.Functor<$><*> ValidatedData.Functor.IdentityIdentityGHC.ShowShowData.Traversable Traversable SemigroupJustNothingversion getBinDir getLibDir getDynLibDir getDataDir getLibexecDir getSysconfDirgetDataFileName