Issue davegurnell#1: Context switching working. More tests needed.

core/src/main/scala/checklist/CanLift.scala

@@ -5,7 +5,7 @@ import scala.language.higherKinds
 
 
 trait NaturalTransformationLowPriorityImplicits {
-  implicit def applicativeTransform[C[_[_]], F[_]](implicit evF: C[F], evCF: C[F] <:< Applicative[F]): Id ~> F = new (Id ~> F) {
+  implicit def applicativeTransform[F[_]](implicit evF: Applicative[F]): Id ~> F = new (Id ~> F) {
     override def apply[A](a: Id[A]): F[A] = evF.pure(a)
   }
 }

core/src/main/scala/checklist/Rule1Syntax.scala

@@ -15,51 +15,19 @@ trait Rule1Syntax {
   }
 
   implicit class Rule1Ops[F[_] : Applicative, A](self: Check[F, A]) {
-//    private def andSame(that: Rule[F, A, A]): Rule[F, A, A] =
-//      (self, that).mapN((x, _) => x)
-
     def and[G[_] : Applicative, R[_]](that: Check[G, A])(implicit canLift: CanLift[Applicative, F, G, R]): Rule[R, A, A] = {
       implicit val evApplicativeR: Applicative[R] = canLift.evR
 
       (self.liftWith(canLift.liftF), that.liftWith(canLift.liftG)).mapN((x, _) => x)
     }
 
-/*
-    def field[B, G[_] : Applicative, R[_]](field: String, accessor: A => B)(validator: Validator[B, G])(implicit canLift: CanLift[F, G, R]): Validator[A, R] =
-      this and (validator contramap accessor prefix field)
-
-    def field[B, G[_] : Applicative, R[_]](accessor: A => B)(validator: Validator[B, G])(implicit canLift: CanLift[F, G, R]): Validator[A, R] =
-    macro ValidationMacros.field[A, B, F, G, R]
-
-    def fieldImplicit[B, G[_] : Applicative, R[_]](field: String, accessor: A => B)(implicit validator: Validator[B, G], canLift: CanLift[F, G, R]): Validator[A, R] =
-      this.field(field, accessor)(validator)
-
-    def fieldImplicit[B, G[_] : Applicative, R[_]](accessor: A => B)(implicit validator: Validator[B, G], canLift: CanLift[F, G, R]): Validator[A, R] =
-    macro ValidationMacros.fieldImplicit[A, B, F, G, R]
-
-    def fieldWith[B, G[_] : Applicative, R[_]](field: String, accessor: A => B)(validatorBuilder: A => Validator[B, G])(implicit canLift: CanLift[F, G, R]): Validator[A, R] =
-      this and Validator[A, G] { value =>
-        val validator = validatorBuilder(value) contramap accessor prefix field
-        validator(value)
-      }
-
-    def fieldWith[B, G[_] : Applicative, R[_]](accessor: A => B)(validatorBuilder: A => Validator[B, G])(implicit canLift: CanLift[F, G, R]): Validator[A, R] =
-    macro ValidationMacros.fieldWith[A, B, F, G, R]
-
-
-    def fieldWithImplicit[B, G[_] : Applicative, R[_]](field: String, accessor: A => B)(implicit validatorBuilder: A => Validator[B, G], canLift: CanLift[F, G, R]): Validator[A, R] =
-      this.fieldWith(field, accessor)(validatorBuilder)
-
-    def fieldWithImplicit[B, G[_] : Applicative, R[_]](accessor: A => B)(implicit validatorBuilder: A => Validator[B, G], canLift: CanLift[F, G, R]): Validator[A, R] =
-    macro ValidationMacros.fieldWithImplicit[A, B, F, G, R]
-    */
-
     def field[G[_] : Applicative, R[_], B](path: Path, lens: Lens[A, B])(rule: Rule[G, B, B])(implicit canLift: CanLift[Applicative, F, G, R]): Rule[R, A, A] =
       self and rule.at(path, lens)
 
     def field[G[_] : Applicative, R[_], B](accessor: A => B)(rule: Rule[G, B, B])(implicit canLift: CanLift[Applicative, F, G, R]): Rule[R, A, A] =
     macro RuleMacros.field[F, G, R, A, B]
 
+    // This is not really working, the compiler can't unify. We should try with embedded class with apply().
     def fieldImplicit[G[_] : Applicative, R[_], B](path: Path, lens: Lens[A, B])(implicit rule: Rule[G, B, B], canLift: CanLift[Applicative, F, G, R]): Rule[R, A, A] =
       field(path, lens)(rule)
 

core/src/test/scala/checklist/ContextSpec.scala

@@ -0,0 +1,22 @@
+package checklist
+
+import cats._
+import cats.data.Ior
+import cats.implicits._
+import org.scalatest.{FreeSpec, Matchers}
+
+import scala.concurrent.Future
+import scala.concurrent.ExecutionContext.Implicits.global
+
+class ContextSpec extends FreeSpec with Matchers {
+
+  "pass" in {
+    val rule1 = Rule.pass[Int]
+    val rule2 = rule1.liftTo[Future]
+    val combined1 = rule1 and rule2
+    val combined2 = rule2 and rule1
+    combined1(+1) map (_ should be(Ior.right(+1)))
+    combined2(+1) map (_ should be(Ior.right(+1)))
+  }
+
+}