package dotty.tools.dotc.core
import Types._, Symbols._, Contexts._
/** Substitution operations on types. See the corresponding `subst` and
* `substThis` methods on class Type for an explanation.
*/
object Substituters {
class SubstOps(val tp: Type) extends AnyVal {
def subst(from: PolyType, to: PolyType, map: SubstPolyMap = null)(implicit ctx: Context): Type =
tp match {
case tp @ PolyParam(pt, n) =>
if (pt eq from) PolyParam(to, n) else tp
case tp: NamedType =>
if (tp.symbol.isStatic) tp
else tp.derivedNamedType(tp.prefix.subst(from, to, map), tp.name)
case ThisType(_)
| MethodParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new SubstPolyMap(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
def subst(from: MethodType, to: MethodType, map: SubstMethodMap)(implicit ctx: Context): Type =
tp match {
case tp @ MethodParam(mt, n) =>
if (mt eq from) MethodParam(to, n) else tp
case tp: NamedType =>
if (tp.symbol.isStatic) tp
else tp.derivedNamedType(tp.prefix.subst(from, to, map), tp.name)
case ThisType(_)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new SubstMethodMap(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
def subst1(from: Symbol, to: Type, map: Subst1Map)(implicit ctx: Context): Type = {
tp match {
case tp: NamedType =>
val sym = tp.symbol
if (tp.prefix eq NoPrefix) {
if (sym eq from) return to
}
if (sym.isStatic) tp
else tp.derivedNamedType(tp.prefix.subst1(from, to, map), tp.name)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new Subst1Map(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
}
def subst2(from1: Symbol, to1: Type, from2: Symbol, to2: Type, map: Subst2Map)(implicit ctx: Context): Type = {
tp match {
case tp: NamedType =>
val sym = tp.symbol
if (tp.prefix eq NoPrefix) {
if (sym eq from1) return to1
if (sym eq from2) return to2
}
if (sym.isStatic) tp
else tp.derivedNamedType(tp.prefix.subst2(from1, to1, from2, to2, map), tp.name)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new Subst2Map(from1, to1, from2, to2)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
}
def subst(from: List[Symbol], to: List[Type], map: SubstMap)(implicit ctx: Context): Type = {
tp match {
case tp: NamedType =>
val sym = tp.symbol
if (tp.prefix eq NoPrefix) {
var fs = from
var ts = to
while (fs.nonEmpty) {
if (fs.head eq sym) return ts.head
fs = fs.tail
ts = ts.tail
}
}
if (sym.isStatic) tp
else tp.derivedNamedType(tp.prefix.subst(from, to, map), tp.name)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new SubstMap(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
}
def substThis(from: ClassSymbol, to: Type, map: SubstThisMap)(implicit ctx: Context): Type =
tp match {
case tp @ ThisType(clazz) =>
if (clazz eq from) to else tp
case tp: NamedType =>
if (tp.symbol.isStatic) tp
else tp.derivedNamedType(tp.prefix.substThis(from, to, map), tp.name)
case MethodParam(_, _)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new SubstThisMap(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
def substThis(from: RefinedType, to: Type, map: SubstRefinedThisMap)(implicit ctx: Context): Type =
tp match {
case tp @ RefinedThis(rt) =>
if (rt eq from) to else tp
case tp: NamedType =>
if (tp.symbol.isStatic) tp
else tp.derivedNamedType(tp.prefix.substThis(from, to, map), tp.name)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _)
| NoPrefix => tp
case _ =>
val substMap = if (map != null) map else new SubstRefinedThisMap(from, to)
tp match {
case tp: AppliedType =>
tp.derivedAppliedType(
substMap(tp.tycon), tp.typeArgs mapConserve substMap)
case _ =>
substMap mapOver tp
}
}
}
class SubstPolyMap(from: PolyType, to: PolyType)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp.subst(from, to, this)
}
class SubstMethodMap(from: MethodType, to: MethodType)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp.subst(from, to, this)
}
class Subst1Map(from: Symbol, to: Type)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp.subst1(from, to, this)
}
class Subst2Map(from1: Symbol, to1: Type, from2: Symbol, to2: Type)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp.subst2(from1, to1, from2, to2, this)
}
class SubstMap(from: List[Symbol], to: List[Type])(implicit ctx: Context) extends TypeMap {
def apply(tp: Type): Type = tp.subst(from, to, this)
}
class SubstThisMap(from: ClassSymbol, to: Type)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type): Type = tp.substThis(from, to, this)
}
class SubstRefinedThisMap(from: RefinedType, to: Type)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type): Type = tp.substThis(from, to, this)
}
}