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-rw-r--r--core/shared/src/main/scala/magnolia.scala80
1 files changed, 32 insertions, 48 deletions
diff --git a/core/shared/src/main/scala/magnolia.scala b/core/shared/src/main/scala/magnolia.scala
index 9190c1d..1ec6649 100644
--- a/core/shared/src/main/scala/magnolia.scala
+++ b/core/shared/src/main/scala/magnolia.scala
@@ -14,6 +14,8 @@
*/
package magnolia
+import scala.annotation.compileTimeOnly
+import scala.collection.breakOut
import scala.collection.mutable
import scala.language.existentials
import scala.language.higherKinds
@@ -95,42 +97,34 @@ object Magnolia {
val prefixObject = prefixType.typeSymbol
val prefixName = prefixObject.name.decodedName
+ def error(msg: String) = c.abort(c.enclosingPosition, msg)
+
val typeDefs = prefixType.baseClasses.flatMap { cls =>
cls.asType.toType.decls.filter(_.isType).find(_.name.toString == "Typeclass").map { tpe =>
tpe.asType.toType.asSeenFrom(prefixType, cls)
}
}
- val typeConstructor = typeDefs.headOption.fold {
- c.abort(
- c.enclosingPosition,
- s"magnolia: the derivation $prefixObject does not define the Typeclass type constructor"
- )
- }(_.typeConstructor)
+ val typeConstructor = typeDefs.headOption.fold(
+ error(s"magnolia: the derivation $prefixObject does not define the Typeclass type constructor")
+ )(_.typeConstructor)
def checkMethod(termName: String, category: String, expected: String): Unit = {
val term = TermName(termName)
val combineClass = c.prefix.tree.tpe.baseClasses
- .find { cls =>
- cls.asType.toType.decl(term) != NoSymbol
- }
- .getOrElse {
- c.abort(
- c.enclosingPosition,
- s"magnolia: the method `$termName` must be defined on the derivation $prefixObject to derive typeclasses for $category"
- )
- }
+ .find(cls => cls.asType.toType.decl(term) != NoSymbol)
+ .getOrElse(error(s"magnolia: the method `$termName` must be defined on the derivation $prefixObject to derive typeclasses for $category"))
+
val firstParamBlock = combineClass.asType.toType.decl(term).asTerm.asMethod.paramLists.head
if (firstParamBlock.lengthCompare(1) != 0)
- c.abort(c.enclosingPosition,
- s"magnolia: the method `combine` should take a single parameter of type $expected")
+ error(s"magnolia: the method `combine` should take a single parameter of type $expected")
}
// FIXME: Only run these methods if they're used, particularly `dispatch`
checkMethod("combine", "case classes", "CaseClass[Typeclass, _]")
checkMethod("dispatch", "sealed traits", "SealedTrait[Typeclass, _]")
- val removeDeferred = new Transformer {
+ val expandDeferred = new Transformer {
override def transform(tree: Tree) = tree match {
case q"$magnolia.Deferred.apply[$_](${Literal(Constant(method: String))})"
if magnolia.symbol == magnoliaPkg =>
@@ -155,12 +149,11 @@ object Magnolia {
.filterNot(_.isEmpty)
.orElse(directInferImplicit(genericType, typeConstructor))
.getOrElse {
- val missingType = stack.top.fold(searchType)(_.searchType.asInstanceOf[Type])
+ val missingType = stack.top.fold(searchType)(_.searchType)
val typeClassName = s"${missingType.typeSymbol.name.decodedName}.Typeclass"
val genericType = missingType.typeArgs.head
val trace = stack.trace.mkString(" in ", "\n in ", "\n")
- c.abort(c.enclosingPosition,
- s"magnolia: could not find $typeClassName for type $genericType\n$trace")
+ error(s"magnolia: could not find $typeClassName for type $genericType\n$trace")
}
}
}
@@ -295,7 +288,7 @@ object Magnolia {
}
val assignments = caseParams.zip(defaults).zip(annotations).zipWithIndex.map {
- case (((CaseParam(param, repeated, typeclass, paramType, ref), defaultVal), annList), idx) =>
+ case (((CaseParam(param, repeated, _, paramType, ref), defaultVal), annList), idx) =>
q"""$paramsVal($idx) = $magnoliaPkg.Magnolia.param[$typeConstructor, $genericType,
$paramType](
${param.name.decodedName.toString},
@@ -349,7 +342,7 @@ object Magnolia {
s"magnolia: could not find any direct subtypes of $typeSymbol",
force = true)
- c.abort(c.enclosingPosition, "")
+ error("")
}
val subtypesVal: TermName = TermName(c.freshName("subtypes"))
@@ -401,12 +394,8 @@ object Magnolia {
val result = stack
.find(searchType)
- .map { enclosingRef =>
- q"$magnoliaPkg.Deferred[$searchType](${enclosingRef.toString})"
- }
- .orElse {
- directInferImplicit(genericType, typeConstructor)
- }
+ .map(enclosingRef => q"$magnoliaPkg.Deferred[$searchType](${enclosingRef.toString})")
+ .orElse(directInferImplicit(genericType, typeConstructor))
for (tree <- result) if (debug.isDefined && genericType.toString.contains(debug.get)) {
c.echo(c.enclosingPosition, s"Magnolia macro expansion for $genericType")
@@ -415,11 +404,10 @@ object Magnolia {
val dereferencedResult =
if (stack.nonEmpty) result
- else for (tree <- result) yield c.untypecheck(removeDeferred.transform(tree))
+ else for (tree <- result) yield c.untypecheck(expandDeferred.transform(tree))
dereferencedResult.getOrElse {
- c.abort(c.enclosingPosition,
- s"magnolia: could not infer $prefixName.Typeclass for type $genericType")
+ error(s"magnolia: could not infer $prefixName.Typeclass for type $genericType")
}
}
@@ -479,7 +467,8 @@ object Magnolia {
private[magnolia] final case class DirectlyReentrantException()
extends Exception("attempt to recurse directly")
-private[magnolia] object Deferred { def apply[T](method: String): T = ??? }
+@compileTimeOnly("magnolia.Deferred is used for derivation of recursive typeclasses")
+object Deferred { def apply[T](method: String): T = ??? }
private[magnolia] object CompileTimeState {
@@ -492,7 +481,7 @@ private[magnolia] object CompileTimeState {
final case class ChainedImplicit(typeClassName: String, typeName: String)
extends TypePath(s"chained implicit $typeClassName for type $typeName")
- final class Stack[C <: whitebox.Context] {
+ final class Stack[C <: whitebox.Context with Singleton] {
private var frames = List.empty[Frame]
private val cache = mutable.Map.empty[C#Type, C#Tree]
@@ -511,25 +500,18 @@ private[magnolia] object CompileTimeState {
case Frame(_, tpe, term) if tpe =:= searchType => term
}
- def recurse[T <: C#Tree](frame: Frame, searchType: C#Type)(fn: => T): T = {
+ def recurse[T <: C#Tree](frame: Frame, searchType: C#Type)(fn: => C#Tree): C#Tree = {
push(frame)
val result = cache.getOrElseUpdate(searchType, fn)
pop()
- result.asInstanceOf[T]
+ result
}
def trace: List[TypePath] =
- frames
- .drop(1)
- .foldLeft[(C#Type, List[TypePath])]((null, Nil)) {
- case ((_, Nil), frame) =>
- (frame.searchType, frame.path :: Nil)
- case (continue @ (tpe, acc), frame) =>
- if (tpe =:= frame.searchType) continue
- else (frame.searchType, frame.path :: acc)
- }
- ._2
- .reverse
+ (frames.drop(1), frames).zipped.collect {
+ case (Frame(path, tp1, _), Frame(_, tp2, _))
+ if !(tp1 =:= tp2) => path
+ } (breakOut)
override def toString: String =
frames.mkString("magnolia stack:\n", "\n", "\n")
@@ -538,7 +520,9 @@ private[magnolia] object CompileTimeState {
}
object Stack {
- private val global = new Stack[whitebox.Context]
+ // Cheating to satisfy Singleton bound (which improves type inference).
+ private val dummyContext: whitebox.Context = null
+ private val global = new Stack[dummyContext.type]
private val workSet = mutable.Set.empty[whitebox.Context#Symbol]
def withContext(c: whitebox.Context)(fn: Stack[c.type] => c.Tree): c.Tree = {
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-29 01:43:40 +0000