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Compiler for the Scala Programming Language
package scala.reflect.reify
package utils
trait Extractors {
self: Utils =>
import global._
import definitions._
import Flag._
// Example of a reified tree for `reify(List(1, 2))`:
// (also contains an example of a reified type as a third argument to the constructor of Expr)
// {
// val $u: reflect.runtime.universe.type = scala.reflect.runtime.`package`.universe;
// val $m: $u.Mirror = $u.runtimeMirror(Test.this.getClass().getClassLoader());
// $u.Expr[List[Int]]($m, {
// final class $treecreator1 extends scala.reflect.api.TreeCreator {
// def (): $treecreator1 = {
// $treecreator1.super.();
// ()
// };
// def apply[U >: Nothing <: scala.reflect.api.Universe with Singleton]($m$untyped: scala.reflect.api.Mirror[U]): U#Tree = {
// val $u: U = $m$untyped.universe;
// val $m: $u.Mirror = $m$untyped.asInstanceOf[$u.Mirror];
// $u.Apply($u.Select($u.Select($u.build.This($m.staticPackage("scala.collection.immutable").moduleClass), $u.newTermName("List")), $u.newTermName("apply")), List($u.Literal($u.Constant(1)), $u.Literal($u.Constant(2))))
// }
// };
// new $treecreator1()
// })($u.TypeTag[List[Int]]($m, {
// final class $typecreator1 extends scala.reflect.api.TypeCreator {
// def (): $typecreator1 = {
// $typecreator1.super.();
// ()
// };
// def apply[U >: Nothing <: scala.reflect.api.Universe with Singleton]($m$untyped: scala.reflect.api.Mirror[U]): U#Type = {
// val $u: U = $m$untyped.universe;
// val $m: $u.Mirror = $m$untyped.asInstanceOf[$u.Mirror];
// $u.TypeRef($u.ThisType($m.staticPackage("scala.collection.immutable").moduleClass), $m.staticClass("scala.collection.immutable.List"), List($m.staticClass("scala.Int").toTypeConstructor))
// }
// };
// new $typecreator1()
// }))
// }
private def mkCreator(flavor: TypeName, symtab: SymbolTable, rtree: Tree): Tree = {
val tparamu = newTypeName("U")
val (reifierBase, reifierName, reifierTpt, reifierUniverse) = flavor match {
case tpnme.REIFY_TYPECREATOR_PREFIX => (TypeCreatorClass, nme.apply, SelectFromTypeTree(Ident(tparamu), tpnme.Type), ApiUniverseClass)
case tpnme.REIFY_TREECREATOR_PREFIX => (TreeCreatorClass, nme.apply, SelectFromTypeTree(Ident(tparamu), tpnme.Tree), ApiUniverseClass)
case _ => throw new Error(s"unexpected flavor $flavor")
}
val reifierBody = {
def gc(symtab: SymbolTable): SymbolTable = {
def loop(symtab: SymbolTable): SymbolTable = {
def extractNames(tree: Tree) = tree.collect{ case ref: RefTree => ref.name }.toSet
val usedNames = extractNames(rtree) ++ symtab.syms.flatMap(sym => extractNames(symtab.symDef(sym)))
symtab filterAliases { case (_, name) => usedNames(name) }
}
var prev = symtab
var next = loop(symtab)
while (next.syms.length < prev.syms.length) {
prev = next
next = loop(prev)
}
next
}
val universeAlias = ValDef(NoMods, nme.UNIVERSE_SHORT, Ident(tparamu), Select(Ident(nme.MIRROR_UNTYPED), nme.universe))
val mirrorAlias = ValDef(NoMods, nme.MIRROR_SHORT, Select(Ident(nme.UNIVERSE_SHORT), tpnme.Mirror), TypeApply(Select(Ident(nme.MIRROR_UNTYPED), nme.asInstanceOf_), List(Select(Ident(nme.UNIVERSE_SHORT), tpnme.Mirror))))
val trimmedSymtab = if (hasReifier) gc(symtab) else symtab
Block(universeAlias :: mirrorAlias :: trimmedSymtab.encode, rtree)
}
val tpec = ClassDef(
Modifiers(FINAL),
newTypeName(global.currentUnit.fresh.newName(flavor.toString)),
List(),
Template(List(Ident(reifierBase)),
emptyValDef,
List(
DefDef(NoMods, nme.CONSTRUCTOR, List(), List(List()), TypeTree(), Block(List(Apply(Select(Super(This(tpnme.EMPTY), tpnme.EMPTY), nme.CONSTRUCTOR), List())), Literal(Constant(())))),
DefDef(NoMods,
reifierName,
List(TypeDef(Modifiers(PARAM), tparamu, List(), TypeBoundsTree(Ident(NothingClass), CompoundTypeTree(Template(List(Ident(reifierUniverse), Ident(SingletonClass)), emptyValDef, List()))))),
List(List(ValDef(Modifiers(PARAM), nme.MIRROR_UNTYPED, AppliedTypeTree(Ident(MirrorClass), List(Ident(tparamu))), EmptyTree))),
reifierTpt, reifierBody))))
Block(tpec, ApplyConstructor(Ident(tpec.name), List()))
}
private def mkWrapper(universe: Tree, mirror: Tree, wrappee: Tree): Tree = {
val universeAlias = ValDef(NoMods, nme.UNIVERSE_SHORT, SingletonTypeTree(universe), universe)
val mirrorAlias = ValDef(NoMods, nme.MIRROR_SHORT, Select(Ident(nme.UNIVERSE_SHORT), tpnme.Mirror), mirror orElse mkDefaultMirrorRef(global)(universe, typer))
Block(List(universeAlias, mirrorAlias), wrappee)
}
// if we're reifying a MethodType, we can't use it as a type argument for TypeTag ctor
// http://groups.google.com/group/scala-internals/browse_thread/thread/2d7bb85bfcdb2e2
private def mkTarg(tpe: Type): Tree = (
if ((tpe eq null) || !isUseableAsTypeArg(tpe)) TypeTree(AnyTpe)
else TypeTree(tpe)
)
object ReifiedTree {
def apply(universe: Tree, mirror: Tree, symtab: SymbolTable, rtree: Tree, tpe: Type, rtpe: Tree, concrete: Boolean): Tree = {
val tagFactory = if (concrete) nme.TypeTag else nme.WeakTypeTag
val tagCtor = TypeApply(Select(Select(Ident(nme.UNIVERSE_SHORT), tagFactory), nme.apply), List(mkTarg(tpe)))
val exprCtor = TypeApply(Select(Select(Ident(nme.UNIVERSE_SHORT), nme.Expr), nme.apply), List(mkTarg(tpe)))
val tagArgs = List(Ident(nme.MIRROR_SHORT), mkCreator(tpnme.REIFY_TYPECREATOR_PREFIX, symtab, rtpe))
val unwrapped = Apply(Apply(exprCtor, List(Ident(nme.MIRROR_SHORT), mkCreator(tpnme.REIFY_TREECREATOR_PREFIX, symtab, rtree))), List(Apply(tagCtor, tagArgs)))
mkWrapper(universe, mirror, unwrapped)
}
def unapply(tree: Tree): Option[(Tree, Tree, SymbolTable, Tree, Type, Tree, Boolean)] = tree match {
case Block(
List(udef @ ValDef(_, _, _, universe), mdef @ ValDef(_, _, _, mirror)),
Apply(
Apply(TypeApply(_, List(ttpe @ TypeTree())), List(_, Block(List(ClassDef(_, _, _, Template(_, _, List(_, DefDef(_, _, _, _, _, Block(_ :: _ :: symbolTable1, rtree)))))), _))),
// todo. doesn't take into account optimizations such as $u.TypeTag.Int or the upcoming closure optimization
List(Apply(TypeApply(tagFactory @ Select(_, _), _), List(_, Block(List(ClassDef(_, _, _, Template(_, _, List(_, DefDef(_, _, _, _, _, Block(_ :: _ :: symbolTable2, rtpe)))))), _))))))
if udef.name == nme.UNIVERSE_SHORT && mdef.name == nme.MIRROR_SHORT =>
val tagFlavor = tagFactory match {
case Select(Select(_, tagFlavor), _) => tagFlavor
case Select(_, tagFlavor) => tagFlavor
}
Some((universe, mirror, SymbolTable(symbolTable1 ++ symbolTable2), rtree, ttpe.tpe, rtpe, tagFlavor == nme.TypeTag))
case _ =>
None
}
}
object ReifiedType {
def apply(universe: Tree, mirror: Tree, symtab: SymbolTable, tpe: Type, rtpe: Tree, concrete: Boolean) = {
val tagFactory = if (concrete) nme.TypeTag else nme.WeakTypeTag
val ctor = TypeApply(Select(Select(Ident(nme.UNIVERSE_SHORT), tagFactory), nme.apply), List(mkTarg(tpe)))
val args = List(Ident(nme.MIRROR_SHORT), mkCreator(tpnme.REIFY_TYPECREATOR_PREFIX, symtab, rtpe))
val unwrapped = Apply(ctor, args)
mkWrapper(universe, mirror, unwrapped)
}
def unapply(tree: Tree): Option[(Tree, Tree, SymbolTable, Type, Tree, Boolean)] = tree match {
case Block(
List(udef @ ValDef(_, _, _, universe), mdef @ ValDef(_, _, _, mirror)),
// todo. doesn't take into account optimizations such as $u.TypeTag.Int or the upcoming closure optimization
Apply(TypeApply(tagFactory @ Select(_, _), List(ttpe @ TypeTree())), List(_, Block(List(ClassDef(_, _, _, Template(_, _, List(_, DefDef(_, _, _, _, _, Block(_ :: _ :: symtab, rtpe)))))), _))))
if udef.name == nme.UNIVERSE_SHORT && mdef.name == nme.MIRROR_SHORT =>
val tagFlavor = tagFactory match {
case Select(Select(_, tagFlavor), _) => tagFlavor
case Select(_, tagFlavor) => tagFlavor
}
Some((universe, mirror, SymbolTable(symtab), ttpe.tpe, rtpe, tagFlavor == nme.TypeTag))
case _ =>
None
}
}
object TreeSplice {
def apply(splicee: Tree): Tree =
Select(splicee, ExprSplice)
def unapply(tree: Tree): Option[Tree] = tree match {
case Select(splicee, _) if tree.symbol != NoSymbol && tree.symbol == ExprSplice =>
Some(splicee)
case _ =>
None
}
}
object FreeDef {
def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
case FreeTermDef(uref, name, binding, flags, origin) =>
Some((uref, name, binding, flags, origin))
case FreeTypeDef(uref, name, binding, flags, origin) =>
Some((uref, name, binding, flags, origin))
case _ =>
None
}
}
object FreeTermDef {
def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
case
ValDef(_, name, _, Apply(
Select(Select(uref1 @ Ident(_), build1), newFreeTerm),
List(
_,
_,
Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))),
Literal(Constant(origin: String)))))
if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newFreeTerm == nme.newFreeTerm &&
uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
Some(uref1, name, reifyBinding(tree), flags, origin)
case _ =>
None
}
}
object FreeTypeDef {
def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
case
ValDef(_, name, _, Apply(
Select(Select(uref1 @ Ident(_), build1), newFreeType),
List(
_,
Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))),
Literal(Constant(origin: String)))))
if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newFreeType == nme.newFreeType &&
uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
Some(uref1, name, reifyBinding(tree), flags, origin)
case _ =>
None
}
}
object FreeRef {
def unapply(tree: Tree): Option[(Tree, TermName)] = tree match {
case Apply(Select(Select(uref @ Ident(_), build), ident), List(Ident(name: TermName)))
if build == nme.build && ident == nme.Ident && name.startsWith(nme.REIFY_FREE_PREFIX) =>
Some((uref, name))
case _ =>
None
}
}
object SymDef {
def unapply(tree: Tree): Option[(Tree, TermName, Long, Boolean)] = tree match {
case
ValDef(_, name, _, Apply(
Select(Select(uref1 @ Ident(_), build1), newNestedSymbol),
List(
_,
_,
_,
Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))),
Literal(Constant(isClass: Boolean)))))
if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newNestedSymbol == nme.newNestedSymbol &&
uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
Some((uref1, name, flags, isClass))
case _ =>
None
}
}
object TypeRefToFreeType {
def unapply(tree: Tree): Option[TermName] = tree match {
case Apply(Select(Select(uref @ Ident(_), typeRef), apply), List(Select(_, noSymbol), Ident(freeType: TermName), nil))
if (uref.name == nme.UNIVERSE_SHORT && typeRef == nme.TypeRef && noSymbol == nme.NoSymbol && freeType.startsWith(nme.REIFY_FREE_PREFIX)) =>
Some(freeType)
case _ =>
None
}
}
object BoundTerm {
def unapply(tree: Tree): Option[Tree] = tree match {
case Ident(name) if name.isTermName =>
Some(tree)
case This(_) =>
Some(tree)
case _ =>
None
}
}
object BoundType {
def unapply(tree: Tree): Option[Tree] = tree match {
case Select(_, name) if name.isTypeName =>
Some(tree)
case SelectFromTypeTree(_, name) if name.isTypeName =>
Some(tree)
case Ident(name) if name.isTypeName =>
Some(tree)
case _ =>
None
}
}
}