trash - How to use intermediate result of Reads with another Reads -

the example have validating credit card number string. validations 1) issuer should exist credit card number, , 2) issuer should accepted 1 merchant.

here's work have far. ideally, use intermediate result issuer first reads in next reads. there better way?

   reads.filter[string](validationerror("invalid issuer")) { cardnumber =>       findissuer(cardnumber).isdefined // option[issuer]     } andthen     reads.filter[string](validationerror("issuer not accepted")) { cardnumber => // issuer, check issuer accepted merchant     } 

it's not direct answer, might consider write logic for/yield expression:

val result: either[string, issuer] = {   card <- json.validate[card].aseither.leftmap(_ => "reading error")   issuer <- findissuer(card.number) //returns either[string, _]   _ <- isaccepted(issuer) // returns either[string,_] } yield issuer 

p.s. it's gateway case start using scalaz validation.