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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
** **
\* */
// $Id$
package scalac.transformer;
import scalac.*;
import scalac.util.*;
import scalac.parser.*;
import scalac.symtab.*;
import scalac.checkers.*;
public class LambdaLiftPhase extends PhaseDescriptor implements Kinds, Modifiers {
private Global global;
int nextPhase;
public void initialize(Global global, int id) {
super.initialize(global, id);
this.global = global;
this.nextPhase = id + 1;
}
public String name () {
return "lambdalift";
}
public String description () {
return "lambda lifter";
}
public String taskDescription() {
return "lambda lifting";
}
public Phase createPhase(Global global) {
return new LambdaLift(global, this);
}
public Type transformInfo(Symbol sym, Type tp) {
if (global.debug)
global.log("transform info for " + sym + sym.locationString());
Type tp1 = tp;
if (sym != Symbol.NONE) {
switch (sym.type()) {
case MethodType(_, _):
case PolyType(_, _):
tp1 = transform(tp, sym);
break;
default:
tp1 = transform(tp, sym.owner());
}
}
if ((sym.flags & Modifiers.CAPTURED) != 0) return refType(tp1);
else return tp1;
}
/** Add proxies as type arguments for propagated type parameters.
*/
Type transform(Type tp, Symbol owner) {
return transformTypeMap.setOwner(owner).apply(tp);
}
private class TransformTypeMap extends Type.MapOnlyTypes {
Symbol owner;
Type.Map setOwner(Symbol owner) { this.owner = owner; return this; }
public Type apply(Type tp) {
switch (tp) {
case TypeRef(Type pre, Symbol sym, Type[] targs):
switch (pre) {
case ThisType(_):
if (sym.kind == CLASS && sym.constructor().isUpdated(nextPhase)) {
Symbol[] tparams =
sym.constructor().infoAt(nextPhase).typeParams();
int i = tparams.length;
while (i > 0 && (tparams[i-1].flags & SYNTHETIC) != 0)
i--;
if (i < tparams.length) {
if (global.debug)
global.log("adding proxies for " + sym + ": " + ArrayApply.toString(tparams));
Type[] targs1 = new Type[tparams.length];
System.arraycopy(map(targs), 0, targs1, 0, targs.length);
while (i < tparams.length) {
targs1[i] = proxy(tparams[i], owner).type();
i++;
}
return Type.TypeRef(pre, sym, targs1);
}
}
}
break;
}
return map(tp);
}
/** All symbols are mapped to themselves.
*/
public Scope map(Scope s) { return s; }
public Symbol map(Symbol s) { return s; }
public Symbol[] map(Symbol[] ss) { return ss; }
}
private TransformTypeMap transformTypeMap = new TransformTypeMap();
/** Return closest enclosing (type)parameter that has same name as `fv',
* or `fv' itself if this is the closest definition.
*/
Symbol proxy(Symbol fv, Symbol owner) {
if (global.debug)
global.log("proxy " + fv + " in " + LambdaLift.asFunction(owner));
Symbol o = owner;
while (o.kind != NONE) {
if (global.debug)
global.log("looking in " + LambdaLift.asFunction(o) + " " +
ArrayApply.toString(o.typeParams()));
Symbol fowner = LambdaLift.asFunction(o);
if (fv.owner() == fowner) return fv;
Type ft = (fowner.isUpdated(nextPhase)) ? fowner.typeAt(nextPhase)
: fowner.type();
Symbol[] ownerparams = fv.isType() ? ft.typeParams()
: ft.firstParams();
for (int i = 0; i < ownerparams.length; i++) {
if (ownerparams[i].name == fv.name)
return ownerparams[i];
}
assert o.owner() != o;
o = o.owner();
}
throw new ApplicationError("proxy " + fv + " in " + owner);
}
/** The type scala.Ref[tp]
*/
Type refType(Type tp) {
Symbol refClass = global.definitions.getClass(Names.scala_Ref);
assert refClass.kind == Kinds.CLASS;
return Type.TypeRef(global.definitions.SCALA_TYPE, refClass, new Type[]{tp});
}
public Checker[] postCheckers(Global global) {
return new Checker[] {
new CheckSymbols(global),
new CheckTypes(global),
new CheckOwners(global),
new CheckNames(global)
};
}
}
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