Add isConstant field

fthomas · Jul 18, 2015 · a1859ee · a1859ee
1 parent 1ae93d2
commit a1859ee
Show file tree

Hide file tree

Showing 5 changed files with 43 additions and 15 deletions.
diff --git a/build.sbt b/build.sbt
@@ -81,7 +81,7 @@ lazy val compileSettings = Seq(
   ),
 
   wartremoverErrors in (Compile, compile) ++= Warts.unsafe diff
-    Seq(Wart.Any, Wart.AsInstanceOf, Wart.NonUnitStatements, Wart.Throw)
+    Seq(Wart.Any, Wart.DefaultArguments, Wart.AsInstanceOf, Wart.NonUnitStatements, Wart.Throw)
 )
 
 lazy val scaladocSettings = Seq(

diff --git a/shared/src/main/scala/eu/timepit/refined/Predicate.scala b/shared/src/main/scala/eu/timepit/refined/Predicate.scala
@@ -22,6 +22,8 @@ trait Predicate[P, T] extends Serializable { self =>
   def validate(t: T): Option[String] =
     if (isValid(t)) None else Some(s"Predicate failed: ${show(t)}.")
 
+  val isConstant: Boolean = false
+
   /** Checks if `t` does not satisfy the predicate `P`. */
   final def notValid(t: T): Boolean =
     !isValid(t)
@@ -45,6 +47,7 @@ trait Predicate[P, T] extends Serializable { self =>
       def isValid(u: U): Boolean = self.isValid(f(u))
       def show(u: U): String = self.show(f(u))
       override def validate(u: U): Option[String] = self.validate(f(u))
+      override val isConstant: Boolean = self.isConstant
       override def accumulateIsValid(u: U): List[Boolean] = self.accumulateIsValid(f(u))
       override def accumulateShow(u: U): List[String] = self.accumulateShow(f(u))
     }
@@ -55,10 +58,18 @@ object Predicate {
   def apply[P, T](implicit p: Predicate[P, T]): Predicate[P, T] = p
 
   /** Constructs a [[Predicate]] from its parameters. */
-  def instance[P, T](validateT: T => Boolean, showT: T => String): Predicate[P, T] =
+  def instance[P, T](isValidF: T => Boolean, showF: T => String, constant: Boolean = false): Predicate[P, T] =
     new Predicate[P, T] {
-      def isValid(t: T): Boolean = validateT(t)
-      def show(t: T): String = showT(t)
+      def isValid(t: T): Boolean = isValidF(t)
+      def show(t: T): String = showF(t)
+      override val isConstant: Boolean = constant
+    }
+
+  def constant[P, T](isValidV: Boolean, showV: String): Predicate[P, T] =
+    new Predicate[P, T] {
+      def isValid(t: T): Boolean = isValidV
+      def show(t: T): String = showV
+      override val isConstant: Boolean = true
     }
 
   /**
@@ -79,9 +90,9 @@ object Predicate {
 
   /** Returns a [[Predicate]] that ignores its inputs and always yields `true`. */
   def alwaysValid[P, T]: Predicate[P, T] =
-    instance(_ => true, _ => "true")
+    constant(isValidV = true, "true")
 
   /** Returns a [[Predicate]] that ignores its inputs and always yields `false`. */
   def alwaysInvalid[P, T]: Predicate[P, T] =
-    instance(_ => false, _ => "false")
+    constant(isValidV = false, "false")
 }
diff --git a/shared/src/main/scala/eu/timepit/refined/boolean.scala b/shared/src/main/scala/eu/timepit/refined/boolean.scala
@@ -52,6 +52,8 @@ private[refined] trait BooleanPredicates {
           case Some(_) => None
           case None => Some(s"Predicate ${p.show(t)} did not fail.")
         }
+
+      override val isConstant: Boolean = p.isConstant
     }
 
   implicit def andPredicate[A, B, T](implicit pa: Predicate[A, T], pb: Predicate[B, T]): Predicate[A And B, T] =
@@ -69,6 +71,8 @@ private[refined] trait BooleanPredicates {
             Some(s"Right predicate of ${show(t)} failed: $sr")
           case _ => None
         }
+
+      override val isConstant: Boolean = pa.isConstant && pb.isConstant
     }
 
   implicit def orPredicate[A, B, T](implicit pa: Predicate[A, T], pb: Predicate[B, T]): Predicate[A Or B, T] =
@@ -82,6 +86,8 @@ private[refined] trait BooleanPredicates {
             Some(s"Both predicates of ${show(t)} failed. Left: $sl Right: $sr")
           case _ => None
         }
+
+      override val isConstant: Boolean = pa.isConstant && pb.isConstant
     }
 
   implicit def xorPredicate[A, B, T](implicit pa: Predicate[A, T], pb: Predicate[B, T]): Predicate[A Xor B, T] =
@@ -97,6 +103,8 @@ private[refined] trait BooleanPredicates {
             Some(s"Both predicates of ${show(t)} succeeded.")
           case _ => None
         }
+
+      override val isConstant: Boolean = pa.isConstant && pb.isConstant
     }
 
   implicit def allOfHNilPredicate[T]: Predicate[AllOf[HNil], T] =
@@ -105,7 +113,8 @@ private[refined] trait BooleanPredicates {
   implicit def allOfHConsPredicate[PH, PT <: HList, T](implicit ph: Predicate[PH, T], pt: Predicate[AllOf[PT], T]): Predicate[AllOf[PH :: PT], T] =
     Predicate.instance(
       t => ph.isValid(t) && pt.isValid(t),
-      t => s"(${ph.show(t)} && ${pt.show(t)})"
+      t => s"(${ph.show(t)} && ${pt.show(t)})",
+      ph.isConstant && pt.isConstant
     )
 
   implicit def anyOfHNilPredicate[T]: Predicate[AnyOf[HNil], T] =
@@ -114,7 +123,8 @@ private[refined] trait BooleanPredicates {
   implicit def anyOfHConsPredicate[PH, PT <: HList, T](implicit ph: Predicate[PH, T], pt: Predicate[AnyOf[PT], T]): Predicate[AnyOf[PH :: PT], T] =
     Predicate.instance(
       t => ph.isValid(t) || pt.isValid(t),
-      t => s"(${ph.show(t)} || ${pt.show(t)})"
+      t => s"(${ph.show(t)} || ${pt.show(t)})",
+      ph.isConstant && pt.isConstant
     )
 
   implicit def oneOfHNilPredicate[T]: Predicate[OneOf[HNil], T] =
@@ -125,6 +135,8 @@ private[refined] trait BooleanPredicates {
       def isValid(t: T): Boolean = accumulateIsValid(t).count(identity) == 1
       def show(t: T): String = accumulateShow(t).mkString("oneOf(", ", ", ")")
 
+      override val isConstant: Boolean = ph.isConstant && pt.isConstant
+
       override def accumulateIsValid(t: T): List[Boolean] =
         ph.isValid(t) :: pt.accumulateIsValid(t)
 

diff --git a/shared/src/main/scala/eu/timepit/refined/internal/RefineLit.scala b/shared/src/main/scala/eu/timepit/refined/internal/RefineLit.scala
@@ -17,14 +17,17 @@ object RefineLit {
   def macroImpl[P: c.WeakTypeTag, T: c.WeakTypeTag](c: blackbox.Context)(t: c.Expr[T])(p: c.Expr[Predicate[P, T]]): c.Expr[T @@ P] = {
     import c.universe._
 
-    val litValue: T = t.tree match {
+    val predicate: Predicate[P, T] = MacroUtils.eval(c)(p)
+
+    val tValue: T = t.tree match {
       case Literal(Constant(value)) => value.asInstanceOf[T]
+      case _ if predicate.isConstant => null.asInstanceOf[T]
       case _ => c.abort(c.enclosingPosition, "refineLit only supports literals")
     }
 
-    val predicate: Predicate[P, T] = MacroUtils.eval(c)(p)
-    predicate.validate(litValue) match {
-      case None => c.Expr(q"$t.asInstanceOf[${weakTypeOf[T @@ P]}]")
+    predicate.validate(tValue) match {
+      case None =>
+        c.Expr(q"$t.asInstanceOf[${weakTypeOf[T @@ P]}]")
       case Some(msg) => c.abort(c.enclosingPosition, msg)
     }
   }

diff --git a/shared/src/main/scala/eu/timepit/refined/internal/RefineM.scala b/shared/src/main/scala/eu/timepit/refined/internal/RefineM.scala
@@ -15,13 +15,15 @@ object RefineM {
   def macroImpl[P: c.WeakTypeTag, T: c.WeakTypeTag](c: blackbox.Context)(t: c.Expr[T])(p: c.Expr[Predicate[P, T]]): c.Expr[Refined[T, P]] = {
     import c.universe._
 
-    val litValue: T = t.tree match {
+    val predicate: Predicate[P, T] = MacroUtils.eval(c)(p)
+
+    val tValue: T = t.tree match {
       case Literal(Constant(value)) => value.asInstanceOf[T]
+      case _ if predicate.isConstant => null.asInstanceOf[T]
       case _ => c.abort(c.enclosingPosition, "refineM only supports literals")
     }
 
-    val predicate: Predicate[P, T] = MacroUtils.eval(c)(p)
-    predicate.validate(litValue) match {
+    predicate.validate(tValue) match {
       case None =>
         c.Expr(q"_root_.eu.timepit.refined.Refined[${weakTypeOf[T]}, ${weakTypeOf[P]}]($t)")
       case Some(msg) => c.abort(c.enclosingPosition, msg)