Type Members

1.  case class ConsistentParse[E, A, B](p: Proposition[E, B], parsing: (A) ⇒ ValidatedNel[E, B]) extends Product with Serializable
2.  trait Predicate[-A] extends AnyRef
3.  trait Proposition[+E, -A] extends AnyRef

   A data type for lazy consistency checks on a data structure.

   A data type for lazy consistency checks on a data structure.

   A Proposition wraps a function that checks a proposition of a logical statement over a type. Combinators like leftMap, contramap, &&, ||, and not, can be used to easily create more complex checks.

   val a = Proposition[String, Int](x => if(x > 10) False("age should be less than 10") else True)
   //a: purity.Proposition[String,Int] = Proposition
   
   a.check(21)
   //res0: purity.Truth[String] = False(NonEmptyList(age should be less than 10))
   
   a.check(9)
   //res1: purity.Truth[String] = True
   
   val b = Proposition[String, String](x => if(x.length > 2) False("name code should be less than 3") else True)
   //b: purity.Proposition[String,String] = Proposition
   
   val c = a.contramap[User](_.age) && b.contramap[User](_.name)
   //c: purity.Proposition[String,User] = Proposition
   
   c.check(User("FAF", 21))
   //res3: purity.Truth[String] = False(NonEmptyList(age should be less than 10, name code should be less than 3))

   E

   type of the failure in case of an False result.

   A

   type to be checked for consistency.

4.  sealed trait Truth[+E] extends AnyRef

   Coproduct that represents a logical truth.

   Coproduct that represents a logical truth. Truth is either True or False(e)

   One may also view the Truth data type as an inverse Option, or a cats Validated with the Valid type parameter set to Unit.

   Contains combinators map, not, &&, ||

   E

   type which encodes possible failures (The False data type will contain a non empty list of these)