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package dotty.tools.dotc.transform
import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransform, TreeTransformer}
import dotty.tools.dotc.ast.tpd
import dotty.tools.dotc.core.Contexts.Context
import scala.collection.mutable.ListBuffer
import dotty.tools.dotc.core.{Scopes, Flags}
import dotty.tools.dotc.core.Symbols.NoSymbol
import scala.annotation.tailrec
import dotty.tools.dotc.core._
import Symbols._
import scala.Some
import dotty.tools.dotc.transform.TreeTransforms.{NXTransformations, TransformerInfo, TreeTransform, TreeTransformer}
import dotty.tools.dotc.ast.tpd
import dotty.tools.dotc.core.Contexts.Context
import scala.collection.mutable
import dotty.tools.dotc.core.Names.Name
import NameOps._
/** A transformer that provides a convenient way to create companion objects
*/
abstract class CreateCompanionObjects extends TreeTransform {
import tpd._
/** Given class definition should return true if companion object creation should be enforced
*/
def predicate(cls: TypeDef)(implicit ctx: Context): Boolean
override def transformStats(trees: List[Tree])(implicit ctx: Context, info: TransformerInfo): List[tpd.Tree] = {
@tailrec
def transformStats0(trees: List[Tree], acc: ListBuffer[Tree]): List[Tree] = {
trees match {
case Nil => acc.toList
case (claz: TypeDef) :: stats if claz.symbol.isClass && !(claz.symbol is Flags.Module) => {
val moduleExists = !(claz.symbol.companionModule eq NoSymbol)
if (moduleExists || !predicate(claz)) transformStats0(stats, acc += claz)
else {
val moduleSymbol = ctx.newCompleteModuleSymbol(claz.symbol.owner, claz.name.toTermName, Flags.Synthetic, Flags.Synthetic, List(defn.ObjectClass.typeRef), Scopes.newScope)
if (moduleSymbol.owner.isClass) moduleSymbol.entered
val companion = tpd.ModuleDef(moduleSymbol, List(EmptyTree))
acc += claz
acc += companion
transformStats0(stats, acc)
}
}
case stat :: stats => transformStats0(stats, acc += stat)
}
}
transformStats0(trees, ListBuffer())
}
}
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