diff options
Diffstat (limited to 'core/shared/src/main/scala/magnolia.scala')
| -rw-r--r-- | core/shared/src/main/scala/magnolia.scala | 38 |
1 files changed, 17 insertions, 21 deletions
diff --git a/core/shared/src/main/scala/magnolia.scala b/core/shared/src/main/scala/magnolia.scala index 759deb6..c0fc10d 100644 --- a/core/shared/src/main/scala/magnolia.scala +++ b/core/shared/src/main/scala/magnolia.scala @@ -96,30 +96,26 @@ object Magnolia { } } - val typeclassConstructor = getTypeMember("Typeclass") - - def checkMethod(termName: String, category: String, expected: String): Unit = { + def getMethod(termName: String)(fn: MethodSymbol => Tree): Option[Tree] = { val term = TermName(termName) - val combineClass = prefixType.baseClasses - .find { cls => - cls.asType.toType.decl(term) != NoSymbol - } - .getOrElse { - fail(s"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) - fail(s"the method `combine` should take a single parameter of type $expected") + val cls = prefixType.baseClasses.find(_.asType.toType.decl(term) != NoSymbol) + cls.map(_.asType.toType.decl(term).asTerm.asMethod).map(fn) } - // FIXME: Only run these methods if they're used, particularly `dispatch` - checkMethod("combine", "case classes", "CaseClass[Typeclass, _]") - checkMethod("dispatch", "sealed traits", "SealedTrait[Typeclass, _]") + val typeclassConstructor = getTypeMember("Typeclass") + + lazy val combineMethod = getMethod("combine") { m => q"${c.prefix}.combine" }.getOrElse { + fail("the method `combine` should be defined on the derivation object") + } + + lazy val dispatchMethod = getMethod("dispatch") { m => q"${c.prefix}.dispatch" }.getOrElse { + fail("the method `dispatch` should be defined on the derivation object") + } val removeDeferred = new Transformer { override def transform(tree: Tree) = tree match { - case q"$magnolia.Deferred.apply[$_](${Literal(Constant(method: String))})" - if magnolia.symbol == magnoliaPkg => + case q"$pkg.Deferred.apply[$_](${Literal(Constant(method: String))})" + if pkg.symbol == magnoliaPkg => q"${TermName(method)}" case _ => super.transform(tree) @@ -183,7 +179,7 @@ object Magnolia { val result = if (isCaseObject) { val impl = q""" $typeNameDef - ${c.prefix}.combine($magnoliaPkg.Magnolia.caseClass[$typeConstructor, $genericType]( + $combineMethod($magnoliaPkg.Magnolia.caseClass[$typeConstructor, $genericType]( $typeName, true, false, new $scalaPkg.Array(0), _ => ${genericType.typeSymbol.asClass.module}) ) """ @@ -277,7 +273,7 @@ object Magnolia { $typeNameDef - ${c.prefix}.combine($magnoliaPkg.Magnolia.caseClass[$typeConstructor, $genericType]( + $combineMethod($magnoliaPkg.Magnolia.caseClass[$typeConstructor, $genericType]( $typeName, false, $isValueClass, @@ -342,7 +338,7 @@ object Magnolia { $typeNameDef - ${c.prefix}.dispatch(new $magnoliaPkg.SealedTrait( + $dispatchMethod(new $magnoliaPkg.SealedTrait( $typeName, $subtypesVal: $scalaPkg.Array[$magnoliaPkg.Subtype[$typeConstructor, $genericType]]) ): $resultType |