diff options
Diffstat (limited to 'src/dotty/tools/dotc/ast/UntypedTrees.scala')
| -rw-r--r-- | src/dotty/tools/dotc/ast/UntypedTrees.scala | 465 |
1 files changed, 5 insertions, 460 deletions
diff --git a/src/dotty/tools/dotc/ast/UntypedTrees.scala b/src/dotty/tools/dotc/ast/UntypedTrees.scala index f0488bedf..4af05acfb 100644 --- a/src/dotty/tools/dotc/ast/UntypedTrees.scala +++ b/src/dotty/tools/dotc/ast/UntypedTrees.scala @@ -21,7 +21,7 @@ object untpd extends Trees.Instance[Untyped] { /** mods object name impl */ case class ModuleDef(mods: Modifiers, name: TermName, impl: Template) - extends NameTree with MemberDef { + extends MemberDef { type ThisTree[T >: Untyped] <: Trees.NameTree[T] with Trees.MemberDef[T] with ModuleDef def withName(name: Name) = this.derivedModuleDef(mods, name.toTermName, impl) } @@ -45,8 +45,6 @@ object untpd extends Trees.Instance[Untyped] { // ------ Untyped tree values and creation methods --------------------- - private type VarInfo = (NameTree, Tree) - val unitLiteral = Literal(Constant()) def ref(tp: NamedType)(implicit ctx: Context): Tree = @@ -54,11 +52,11 @@ object untpd extends Trees.Instance[Untyped] { def scalaUnit(implicit ctx: Context) = ref(defn.UnitClass.typeConstructor) - def makeConstructor(mods: Modifiers, vparamss: List[List[ValDef]], rhs: Tree = EmptyTree)(implicit ctx: Context): DefDef = - DefDef(mods, nme.CONSTRUCTOR, Nil, vparamss, TypeTree(), rhs) + def makeConstructor(mods: Modifiers, tparams: List[TypeDef], vparamss: List[List[ValDef]], rhs: Tree = EmptyTree): DefDef = + DefDef(mods, nme.CONSTRUCTOR, tparams, vparamss, TypeTree(), rhs) - def emptyConstructor(implicit ctx: Context): DefDef = - makeConstructor(Modifiers(), Nil) + def emptyConstructor: DefDef = + makeConstructor(Modifiers(), Nil, Nil) def makeSelfDef(name: TermName, tpt: Tree)(implicit ctx: Context) = ValDef(Modifiers(Private), name, tpt, EmptyTree) @@ -81,459 +79,6 @@ object untpd extends Trees.Instance[Untyped] { def refOfDef(tree: NameTree) = Ident(tree.name) -// ------ Untyped tree desugaring ------------------------------------------ - - def desugar(tree: Tree, mode: Mode.Value)(implicit ctx: Context): Tree = { - - def labelDefAndCall(lname: TermName, rhs: Tree, call: Tree) = { - val ldef = DefDef(Modifiers(Label), lname, Nil, ListOfNil, TypeTree(), rhs) - Block(ldef, call) - } - - def derivedValDef(mods: Modifiers, named: NameTree, tpt: Tree, rhs: Tree) = - ValDef(mods, named.name.asTermName, tpt, rhs).withPos(named.pos) - - /** Translate infix operation expression left op right - */ - def makeBinop(left: Tree, op: Name, right: Tree): Tree = { - def assignToNamedArg(arg: Tree) = arg match { - case Assign(Ident(name), rhs) => arg.derivedNamedArg(name, rhs) - case _ => arg - } - if (isLeftAssoc(op)) { - val args: List[Tree] = right match { - case Parens(arg) => assignToNamedArg(arg) :: Nil - case Tuple(args) => args mapConserve assignToNamedArg - case _ => right :: Nil - } - Apply(Select(left, op), args) - } else { - val x = ctx.freshName().toTermName - Block( - ValDef(Modifiers(Synthetic), x, TypeTree(), left), - Apply(Select(right, op), Ident(x))) - } - } - - /** Make closure corresponding to function params => body */ - def makeClosure(params: List[ValDef], body: Tree) = - Block( - DefDef(Modifiers(Synthetic), nme.ANON_FUN, Nil, params :: Nil, EmptyTree, body), - Closure(Nil, Ident(nme.ANON_FUN))) - - /** Make closure corresponding to partial function { cases } */ - def makeCaseClosure(cases: List[CaseDef]) = { - val param = makeSyntheticParameter() - makeClosure(param :: Nil, Match(Ident(param.name), cases)) - } - - /** Create tree for for-comprehension <for (enums) do body> or - * <for (enums) yield body> where mapName and flatMapName are chosen - * corresponding to whether this is a for-do or a for-yield. - * The creation performs the following rewrite rules: - * - * 1. - * - * for (P <- G) E ==> G.foreach (P => E) - * - * Here and in the following (P => E) is interpreted as the function (P => E) - * if P is a variable pattern and as the partial function { case P => E } otherwise. - * - * 2. - * - * for (P <- G) yield E ==> G.map (P => E) - * - * 3. - * - * for (P_1 <- G_1; P_2 <- G_2; ...) ... - * ==> - * G_1.flatMap (P_1 => for (P_2 <- G_2; ...) ...) - * - * 4. - * - * for (P <- G; E; ...) ... - * => - * for (P <- G.filter (P => E); ...) ... - * - * 5. For any N: - * - * for (P_1 <- G; P_2 = E_2; val P_N = E_N; ...) - * ==> - * for (TupleN(P_1, P_2, ... P_N) <- - * for (x_1 @ P_1 <- G) yield { - * val x_2 @ P_2 = E_2 - * ... - * val x_N & P_N = E_N - * TupleN(x_1, ..., x_N) - * } ...) - * - * If any of the P_i are variable patterns, the corresponding `x_i @ P_i' is not generated - * and the variable constituting P_i is used instead of x_i - * - * @param mapName The name to be used for maps (either map or foreach) - * @param flatMapName The name to be used for flatMaps (either flatMap or foreach) - * @param enums The enumerators in the for expression - * @param body The body of the for expression - */ - def makeFor(mapName: TermName, flatMapName: TermName, enums: List[Tree], body: Tree): Tree = { - - /** Make a function value pat => body. - * If pat is a var pattern id: T then this gives (id: T) => body - * Otherwise this gives { case pat => body } - */ - def makeLambda(pat: Tree, body: Tree): Tree = pat match { - case VarPattern(named, tpt) => - makeClosure(derivedValDef(Modifiers(Param), named, tpt, EmptyTree) :: Nil, body) - case _ => - makeCaseClosure(CaseDef(pat, EmptyTree, body) :: Nil) - } - - /** If `pat` is not yet a `Bind` wrap it in one with a fresh name - */ - def makeBind(pat: Tree): Tree = pat match { - case Bind(_, _) => pat - case _ => Bind(ctx.freshName().toTermName, pat) - } - - /** Is pattern `pat` irrefutable when matched against `rhs`? - * We only can do a simple syntactic check here; a more refined check - * is done later prompted by the presence of a "withFilterIfRefutable" call. - */ - def isIrrefutable(pat: Tree, rhs: Tree): Boolean = { - def matchesTuple(pats: List[Tree], rhs: Tree): Boolean = rhs match { - case Tuple(trees) => (pats corresponds trees)(isIrrefutable) - case Parens(rhs1) => matchesTuple(pats, rhs1) - case Block(_, rhs1) => matchesTuple(pats, rhs1) - case If(_, thenp, elsep) => matchesTuple(pats, thenp) && matchesTuple(pats, elsep) - case Match(_, cases) => cases forall (matchesTuple(pats, _)) - case CaseDef(_, _, rhs1) => matchesTuple(pats, rhs) - case Throw(_) => true - case _ => false - } - pat match { - case Bind(_, pat1) => isIrrefutable(pat1, rhs) - case Parens(pat1) => isIrrefutable(pat1, rhs) - case Tuple(pats) => matchesTuple(pats, rhs) - case _ => isVarPattern(pat) - } - } - - /** Make a pattern filter: - * rhs.withFilterIfRefutable { case pat => true case _ => false } - */ - def makePatFilter(rhs: Tree, pat: Tree): Tree = { - val cases = List( - CaseDef(pat, EmptyTree, Literal(Constant(true))), - CaseDef(Ident(nme.WILDCARD), EmptyTree, Literal(Constant(false)))) - Apply(Select(rhs, nme.withFilterIfRefutable), Match(EmptyTree, cases)) - } - - /** rhs.name with a pattern filter on rhs unless `pat` is irrefutable when - * matched against `rhs`. - */ - def rhsSelect(rhs: Tree, name: TermName, pat: Tree) = { - val rhs1 = if (isIrrefutable(pat, rhs)) rhs else makePatFilter(rhs, pat) - Select(rhs1, name) - } - - enums match { - case (enum @ GenFrom(pat, rhs)) :: Nil => - Apply(rhsSelect(rhs, mapName, pat), makeLambda(pat, body)) - case GenFrom(pat, rhs) :: (rest @ (GenFrom(_, _) :: _)) => - val cont = makeFor(mapName, flatMapName, rest, body) - Apply(rhsSelect(rhs, flatMapName, pat), makeLambda(pat, cont)) - case (enum @ GenFrom(pat, rhs)) :: (rest @ GenAlias(_, _) :: _) => - val (valeqs, rest1) = rest.span(_.isInstanceOf[GenAlias]) - val pats = valeqs map { case GenAlias(pat, _) => pat } - val rhss = valeqs map { case GenAlias(_, rhs) => rhs } - val defpat1 = makeBind(pat) - val defpats = pats map makeBind - val pdefs = (defpats, rhss).zipped map (makePatDef(Modifiers(), _, _)) - val ids = (defpat1 :: defpats) map { case Bind(name, _) => Ident(name) } - val rhs1 = makeFor(nme.map, nme.flatMap, GenFrom(defpat1, rhs) :: Nil, Block(pdefs, makeTuple(ids))) - val allpats = pat :: pats - val vfrom1 = GenFrom(makeTuple(allpats), rhs1) - makeFor(mapName, flatMapName, vfrom1 :: rest1, body) - case (enum @ GenFrom(pat, rhs)) :: test :: rest => - val filtered = Apply(rhsSelect(rhs, nme.withFilter, pat), makeLambda(pat, test)) - makeFor(mapName, flatMapName, GenFrom(pat, filtered) :: rest, body) - case _ => - EmptyTree //may happen for erroneous input - } - } - - def makeAnnotated(cls: Symbol, tree: Tree) = - Annotated(TypedSplice(tpd.New(cls.typeConstructor)), tree) - - /** Returns list of all pattern variables, possibly with their types, - * without duplicates - */ - def getVariables(tree: Tree): List[VarInfo] = - getVars(new ListBuffer[VarInfo], tree).toList - - /** In case there is exactly one variable x_1 in pattern - * val/var p = e ==> val/var x_1 = (e: @unchecked) match (case p => (x_1)) - * - * in case there are zero or more than one variables in pattern - * val/var p = e ==> private synthetic val t$ = (e: @unchecked) match (case p => (x_1, ..., x_N)) - * val/var x_1 = t$._1 - * ... - * val/var x_N = t$._N - * If the original pattern variable carries a type annotation, so does the corresponding - * ValDef. - */ - def makePatDef(mods: Modifiers, pat: Tree, rhs: Tree): Tree = pat match { - case VarPattern(named, tpt) => - derivedValDef(mods, named, tpt, rhs) - case _ => - val rhsUnchecked = makeAnnotated(defn.UncheckedAnnot, rhs) - val vars = getVariables(pat) - val ids = for ((named, _) <- vars) yield Ident(named.name) - val caseDef = CaseDef(pat, EmptyTree, makeTuple(ids)) - val matchExpr = Match(rhsUnchecked, caseDef :: Nil) - vars match { - case (named, tpt) :: Nil => - derivedValDef(mods, named, tpt, matchExpr) - case _ => - val tmpName = ctx.freshName().toTermName - val patMods = Modifiers(PrivateLocal | Synthetic | (mods.flags & Lazy)) - val firstDef = ValDef(patMods, tmpName, TypeTree(), matchExpr) - def selector(n: Int) = Select(Ident(tmpName), ("_" + n).toTermName) - val restDefs = - for (((named, tpt), n) <- vars.zipWithIndex) - yield derivedValDef(mods, named, tpt, selector(n)) - Thicket(firstDef :: restDefs) - } - } - - def isPatternVar(id: Ident) = - mode == Mode.Pattern && isVarPattern(id) && id.name != nme.WILDCARD - - // begin desugar - val tree1 = tree match { // todo: move general tree desugaring to typer, and keep only untyped trees here? - case id @ Ident(_) if isPatternVar(id) => - Bind(id.name, Ident(nme.WILDCARD)) - case Typed(id @ Ident(_), tpt) if isPatternVar(id) => - Bind(id.name, Typed(Ident(nme.WILDCARD), tpt)).withPos(id.pos) - case New(templ: Template) => - desugarAnonClass(templ) - case Assign(Apply(fn, args), rhs) => - Apply(Select(fn, nme.update), args :+ rhs) - case If(cond, thenp, EmptyTree) => - If(cond, thenp, unitLiteral) - case Match(EmptyTree, cases) => - makeCaseClosure(cases) - case DefDef(mods, name, tparams, vparamss, tpt, rhs) => - val (tparams1, vparamss1) = - desugarContextBounds(tparams, vparamss, ofClass = false) - tree.derivedDefDef(mods, name, tparams1, vparamss1, tpt, rhs) - case ClassDef( - mods, name, tparams, impl @ Template(constr, parents, self, body)) => - val (tparams1, vparamss1) = - desugarContextBounds(tparams, constr.vparamss, ofClass = true) - val constr1 = constr.derivedDefDef( - constr.mods, constr.name, constr.tparams, vparamss1, constr.tpt, constr.rhs) - - val templ1 = impl.derivedTemplate(constr1, parents, self, body) - tree.derivedClassDef(mods, name, tparams1, templ1) - case ModuleDef(mods, name, tmpl @ Template(constr, parents, self, body)) => - // <module> val name: name$ = New(name$) - // <module> final class name$ extends parents { self: name.type => body } - val clsName = name.moduleClassName - val clsRef = Ident(clsName) - val modul = ValDef(mods | ModuleCreationFlags, name, clsRef, New(clsRef, Nil)) - val clsSelf = self.derivedValDef(self.mods, self.name, SingletonTypeTree(Ident(name)), self.rhs) - val clsTmpl = tmpl.derivedTemplate(constr, parents, clsSelf, body) - val cls = ClassDef(mods.toTypeFlags & AccessFlags | ModuleClassCreationFlags, clsName, Nil, clsTmpl) - Thicket(modul, cls) - case SymbolLit(str) => - New(ref(defn.SymbolClass.typeConstructor), (Literal(Constant(str)) :: Nil) :: Nil) - case InterpolatedString(id, strs, elems) => - Apply(Select(Apply(Ident(nme.StringContext), strs), id), elems) - case Function(args, body) => - if (mode == Mode.Type) // FunctionN[args: _*, body] - AppliedTypeTree( - ref(defn.FunctionClass(args.length).typeConstructor), - args :+ body) - else - makeClosure(args.asInstanceOf[List[ValDef]], body) - case InfixOp(l, op, r) => - mode match { - case Mode.Expr => // l.op(r), or val x = r; l.op(x), plus handle named args specially - makeBinop(l, op, r) - case Mode.Pattern => // op(l, r) - Apply(Ident(op), l :: r :: Nil) - case Mode.Type => // op[l, r] - AppliedTypeTree(Ident(op), l :: r :: Nil) - } - case PostfixOp(t, op) => - if (mode == Mode.Type && op == nme.raw.STAR) - AppliedTypeTree(ref(defn.RepeatedParamType), t) - else { - assert(mode == Mode.Expr) - if (op == nme.WILDCARD) tree // desugar later by eta expansion - else Select(t, op) - } - case PrefixOp(op, t) => - if (mode == Mode.Type && op == nme.ARROWkw) - AppliedTypeTree(ref(defn.ByNameParamClass.typeConstructor), t) - else - Select(t, nme.UNARY_PREFIX ++ op) - case Parens(t) => - t - case Tuple(ts) => - def PairTypeTree(l: Tree, r: Tree) = - AppliedTypeTree(ref(defn.PairClass.typeConstructor), l :: r :: Nil) - if (mode == Mode.Type) ts.reduceRight(PairTypeTree) - else if (ts.isEmpty) unitLiteral - else ts.reduceRight(Pair(_, _)) - case WhileDo(cond, body) => - // { <label> def while$(): Unit = if (cond) { body; while$() } ; while$() } - val call = Apply(Ident(nme.WHILE_PREFIX), Nil) - val rhs = If(cond, Block(body, call), unitLiteral) - labelDefAndCall(nme.WHILE_PREFIX, rhs, call) - case DoWhile(body, cond) => - // { label def doWhile$(): Unit = { body; if (cond) doWhile$() } ; doWhile$() } - val call = Apply(Ident(nme.DO_WHILE_PREFIX), Nil) - val rhs = Block(body, If(cond, call, unitLiteral)) - labelDefAndCall(nme.DO_WHILE_PREFIX, rhs, call) - case ForDo(enums, body) => - makeFor(nme.foreach, nme.foreach, enums, body) orElse tree - case ForYield(enums, body) => - makeFor(nme.map, nme.flatMap, enums, body) orElse tree - case PatDef(mods, pats, tpt, rhs) => - val pats1 = if (tpt.isEmpty) pats else pats map (Typed(_, tpt)) - Thicket(pats1 map (makePatDef(mods, _, rhs))) - case _ => - tree - } - tree1 match { - case tree1: NameTree => tree1.withName(tree1.name.encode) - case _ => tree1 - } - }.withPos(tree.pos) - - def desugarContextBounds(tparams: List[TypeDef], vparamss: List[List[ValDef]], ofClass: Boolean): (List[TypeDef], List[List[ValDef]]) = { - val epbuf = new ListBuffer[ValDef] - def makeEvidenceParam(cxBound: Tree): ValDef = ??? - val tparams1 = tparams mapConserve { - case tparam @ TypeDef(mods, name, ttparams, ContextBounds(tbounds, cxbounds)) => - for (cxbound <- cxbounds) { - val accessMods = if (ofClass) PrivateOrLocal else EmptyFlags - val epname = (nme.EVIDENCE_PARAM_PREFIX.toString + epbuf.length).toTermName - epbuf += - ValDef(Modifiers(Implicit | Param | accessMods), epname, cxbound, EmptyTree) - } - tparam.derivedTypeDef(mods, name, ttparams, tbounds) - case tparam => - tparam - } - epbuf.toList match { - case Nil => - (tparams, vparamss) - case evidenceParams => - val vparamss1 = vparamss.reverse match { - case (vparams @ (vparam :: _)) :: rvparamss if vparam.mods is Implicit => - ((vparams ++ evidenceParams) :: rvparamss).reverse - case _ => - vparamss :+ evidenceParams - } - (tparams1, vparamss1) - } - } - - val NotInTypeAccessorFlags = Param | Private | Local - - def desugarClassDef(cdef: ClassDef)(implicit ctx: Context): ClassDef = { - val ClassDef( - mods, name, tparams, impl @ Template(constr, parents, self, body)) = cdef - - // desugar context bounds - val (tparamAccs, vparamAccss) = - desugarContextBounds(tparams, constr.vparamss, ofClass = true) - - val tparams1 = tparams.map(tparam => tparam.derivedTypeDef( - Modifiers(Param), tparam.name, tparam.tparams, tparam.rhs)) - - // ensure parameter list is non-empty - val vparamss1 = - if (vparamAccss.isEmpty) { - if (mods is Case) - ctx.error("case class needs to have at least one parameter list", cdef.pos) - ListOfNil - } - else - vparamAccss.nestedMap(vparam => vparam.derivedValDef( - Modifiers(Param), vparam.name, vparam.tpt, vparam.rhs)) - - val constr1 = constr.derivedDefDef( - constr.mods, constr.name, constr.tparams, vparamss1, constr.tpt, constr.rhs) - - cdef.derivedClassDef(mods, name, tparams1, - impl.derivedTemplate(constr1, parents, self, tparamAccs ::: vparamAccss.flatten ::: body)) - } - - /** Expand to: - * <module> val name: name$ = New(name$) - * <module> final class name$ extends parents { self: name.type => body } - */ - def desugarModuleDef(mdef: ModuleDef): Tree = { - val ModuleDef(mods, name, tmpl @ Template(constr, parents, self, body)) = mdef - val clsName = name.moduleClassName - val clsRef = Ident(clsName) - val modul = ValDef(mods | ModuleCreationFlags, name, clsRef, New(clsRef, Nil)) - val clsSelf = self.derivedValDef(self.mods, self.name, SingletonTypeTree(Ident(name)), self.rhs) - val clsTmpl = tmpl.derivedTemplate(constr, parents, clsSelf, body) - val cls = ClassDef(mods.toTypeFlags & AccessFlags | ModuleClassCreationFlags, clsName, Nil, clsTmpl) - Thicket(modul, cls) - } - - def desugarAnonClass(templ: Template): Tree = { - val x = tpnme.ANON_CLASS - val clsDef = ClassDef(Modifiers(Final), x, Nil, templ) - Block(clsDef, New(Ident(x), Nil)) - } - - object Mode extends Enumeration { - val Type, Expr, Pattern = Value - } - - /** If tree is a variable pattern, return its name and type, otherwise return None. - */ - private object VarPattern { - def unapply(tree: Tree): Option[VarInfo] = tree match { - case id: Ident => Some(id, TypeTree()) - case Typed(id: Ident, tpt) => Some((id, tpt)) - case _ => None - } - } - - /** Traverse pattern and collect all variable names with their types in buffer. - * Works for expanded as well as unexpanded patterns - * - */ - private object getVars extends TreeAccumulator[ListBuffer[VarInfo]] { - override def apply(buf: ListBuffer[VarInfo], tree: Tree): ListBuffer[VarInfo] = { - def seenName(name: Name) = buf exists (_._1.name == name) - def add(named: NameTree, t: Tree): ListBuffer[VarInfo] = - if (seenName(named.name)) buf else buf += ((named, t)) - tree match { - case Bind(nme.WILDCARD, _) => - foldOver(buf, tree) - case tree @ Bind(_, Typed(tree1, tpt)) if !mayBeTypePat(tpt) => - apply(add(tree, tpt), tree1) - case tree @ Bind(_, tree1) => - apply(add(tree, TypeTree()), tree1) - case Typed(id: Ident, t) if isVarPattern(id) => - add(id, t) - case id: Ident if isVarPattern(id) => - add(id, TypeTree()) - case _ => - foldOver(buf, tree) - } - } - } - // ------- A decorator for producing a path to a location -------------- implicit class UntypedTreeDecorator(val self: Tree) extends AnyVal { |