/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
**
** $Id$
\* */
//todo: T {} == T
package scalac.symtab;
import ch.epfl.lamp.util.Position;
import scalac.ApplicationError;
import scalac.util.*;
import scalac.Global;
public class Type implements Modifiers, Kinds, TypeTags {
public static boolean explainSwitch = false;
private static int indent = 0;
public case ErrorType; // not used after analysis
public case AnyType; // not used after analysis
public case NoType;
/** C.this.type
*/
public case ThisType(Symbol sym);
/** pre.sym.type
* sym represents a valueS
*/
public case SingleType(Type pre, Symbol sym) {
assert this instanceof ExtSingleType;
}
/** pre.sym[args]
* sym represents a type
* for example: scala.List[java.lang.String] is coded as
*
* TypeRef(
* SingleType(ThisType(definitions.ROOT_CLASS), definitions.SCALA),
* <List>,
* new Type[]{
* TypeRef(
* SingleType(
* SingleType(ThisType(definitions.ROOT_CLASS), definitions.JAVA),
* definitions.LANG),
* definitions.STRING,
* new Type[]{})}).
*
*/
public case TypeRef(Type pre, Symbol sym, Type[] args) {
assert pre.isLegalPrefix() || pre == ErrorType : pre + "#" + sym;
}
/** parts_1 with ... with parts_n { members }
*/
public case CompoundType(Type[] parts, Scope members) {
assert this instanceof ExtCompoundType;
}
/** synthetic type of a method def ...(vparams): result = ...
*/
public case MethodType(Symbol[] vparams, Type result);
/** synthetic type of a method def ...[tparams]result
* For instance, given def f[a](x: a): a
* f has type PolyType(new Symbol[]{<a>},
* MethodType(new Symbol[]{<x>}, <a>.type()))
*
* if tparams is empty, this is the type of a parameterless method
* def ... =
* For instance, given def f = 1
* f has type PolyType(new Symbol[]{}, <scala.Int>.type())
*/
public case PolyType(Symbol[] tparams, Type result);
/** synthetic type of an overloaded value whose alternatives are
* alts_1, ..., alts_n, with respective types alttypes_1, ..., alttypes_n
*
* For instance, if there are two definitions of `f'
* def f: int
* def f: String
* then there are three symbols:
* ``f1'' corresponding to def f: int
* ``f2'' corresponding to def f: String
* ``f3'' corresponding to both
* f3 has type
* OverloadedType(
* new Symbol[]{<f1>, <f2>},
* new Type[]{PolyType(new Symbol[]{}, <int>),
* PolyType(new Symbol[]{}, <String>),
*
*/
public case OverloadedType(Symbol[] alts, Type[] alttypes);
/** Hidden case to implement delayed evaluation of types.
* No need to pattern match on this type; it will never come up.
*/
public case LazyType();
/** Hidden case to implement local type inference.
* Later phases do not need to match on this type.
*/
public case TypeVar(Type origin, Constraint constr);
/** Hidden cases to implement type erasure.
* Earlier phases do not need to match on these types.
*/
public case UnboxedType(int tag);
public case UnboxedArrayType(Type elemtp);
/** Force evaluation of a lazy type. No cycle
* check is needed; since this is done in Symbol.
* @see Symbol.info().
*/
public void complete(Symbol p) {}
// Creators ---------------------------------------------------------------------
/** An owner-less ThisType
*/
public static Type localThisType = ThisType(Symbol.NONE);
/** An empty Type array */
public static final Type[] EMPTY_ARRAY = new Type[0];
public static SingleType singleType(Type pre, Symbol sym) {
if (pre.isStable() || pre == ErrorType) {
return new ExtSingleType(pre, sym);
} else {
throw new Type.Error(
"malformed type: " + pre + "#" + sym.nameString() + ".type");
}
}
public static TypeRef appliedType(Type tycon, Type[] args) {
switch (tycon) {
case TypeRef(Type pre, Symbol sym, Type[] args1):
if (args == args1) return (TypeRef)tycon;
else return TypeRef(pre, sym, args);
default:
throw new ApplicationError();
}
}
public static CompoundType compoundType(Type[] parts, Scope members,
Symbol clazz) {
ExtCompoundType res = new ExtCompoundType(parts, members);
res.tsym = clazz;
return res;
}
public static CompoundType compoundType(Type[] parts, Scope members) {
ExtCompoundType res = new ExtCompoundType(parts, members);
res.tsym = new ClassSymbol(
Position.NOPOS, Names.COMPOUND_NAME.toTypeName(), Symbol.NONE,
SYNTHETIC | ABSTRACTCLASS);
res.tsym.setInfo(res);
res.tsym.constructor().setInfo(
Type.MethodType(Symbol.EMPTY_ARRAY, Type.NoType));
return res;
}
public static Type typeRef(Type pre, Symbol sym, Type[] args) {
if (pre.isLegalPrefix() || pre == ErrorType)
return TypeRef(pre, sym, args);
else if (sym.kind == ALIAS)
return pre.memberInfo(sym);
else // todo: handle Java-style inner classes
throw new Type.Error(
"malformed type: " + pre + "#" + sym.nameString());
}
static class ExtSingleType extends SingleType {
Type tp = null;
int definedId = -1;
ExtSingleType(Type pre, Symbol sym) {
super(pre, sym);
}
public Type singleDeref() {
if (definedId != Global.instance.currentPhase.id) {
definedId = Global.instance.currentPhase.id;
tp = pre.memberType(sym).resultType();
}
return tp;
}
}
static class ExtCompoundType extends CompoundType {
Symbol tsym;
ExtCompoundType(Type[] parts, Scope members) {
super(parts, members);
}
public Symbol symbol() {
return tsym;
}
void validate() {//debug
for (Scope.Entry e = members.elems; e != Scope.Entry.NONE; e = e.next)
assert e.sym.owner() == tsym;
}
}
void validate() {//debug
}
// Access methods ---------------------------------------------------------------
/** If this is a thistype, named type, applied type, singleton type, or compound type,
* its symbol, otherwise Symbol.NONE.
*/
public Symbol symbol() {
switch (this) {
case ErrorType:
return Symbol.ERROR;
case ThisType(Symbol sym):
return sym;
case TypeRef(_, Symbol sym, _):
return sym;
case SingleType(_, Symbol sym):
return sym;
case TypeVar(Type origin, _):
return origin.symbol();
case CompoundType(_, _):
// overridden in ExtCompoundType
throw new ApplicationError();
default:
return Symbol.NONE;
}
}
public static Symbol[] symbol(Type[] tps) {
Symbol[] syms = new Symbol[tps.length];
for (int i = 0; i < syms.length; i++)
syms[i] = tps[i].symbol();
return syms;
}
/** If this type is a thistype or singleton type, its type,
* otherwise the type itself.
*/
public Type singleDeref() {
switch (this) {
case ThisType(Symbol sym):
return sym.typeOfThis();
case SingleType(Type pre, Symbol sym):
// overridden in ExtSingleType
throw new ApplicationError();
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) return constr.inst.singleDeref();
else return this;
default:
return this;
}
}
/** If this type is a thistype or singleton type, its underlying object type,
* otherwise the type itself.
*/
public Type widen() {
Type tp = singleDeref();
switch (tp) {
case ThisType(_):
case SingleType(_, _):
return tp.widen();
default:
return tp;
}
}
private static Map widenMap = new Map() {
public Type apply(Type t) {
return t.widen();
}
};
public static Type[] widen(Type[] tps) {
return widenMap.map(tps);
}
/** The thistype or singleton type corresponding to values of this type.
*/
public Type narrow() {
switch (this) {
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym.kind == ALIAS) return pre.memberInfo(sym).narrow();
else if (sym.kind == CLASS) return sym.thisType();
else return ThisType(sym);
case CompoundType(_, _):
return symbol().thisType();
default:
return this;
}
}
/** The lower approximation of this type (which must be a typeref)
*/
public Type loBound() {
switch (unalias()) {
case TypeRef(Type pre, Symbol sym, Type[] args):
Type lb = Global.instance.definitions.ALL_TYPE;
if (sym.kind == TYPE) {
lb = pre.memberLoBound(sym);
}
if (lb.symbol() == Global.instance.definitions.ALL_CLASS &&
this.symbol() != Global.instance.definitions.ALL_CLASS &&
this.isSubType(Global.instance.definitions.ANYREF_TYPE)) {
lb = Global.instance.definitions.ALLREF_TYPE;
}
return lb;
default:
throw new ApplicationError();
}
}
/** If this is a this-type, named-type, applied type or single-type, its prefix,
* otherwise NoType.
*/
public Type prefix() {
switch (this) {
case ThisType(Symbol sym): return sym.owner().thisType();
case TypeRef(Type pre, _, _): return pre;
case SingleType(Type pre, _): return pre;
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) return constr.inst.prefix();
else return NoType;
default: return NoType;
}
}
/** Get all type arguments of this type.
*/
public Type[] typeArgs() {
switch (unalias()) {
case TypeRef(_, _, Type[] args):
return args;
default:
return Type.EMPTY_ARRAY;
}
}
/** Get type of `this' symbol corresponding to this type, extend
* homomorphically to function types and poly types.
*/
public Type instanceType() {
switch (unalias()) {
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym != sym.thisSym())
return sym.typeOfThis()
.asSeenFrom(pre, sym.owner())
.subst(sym.typeParams(), args);
break;
case MethodType(Symbol[] params, Type restp):
Type restp1 = restp.instanceType();
if (restp1 != restp)
return MethodType(params, restp1);
break;
case PolyType(Symbol[] tparams, Type restp):
Type restp1 = restp.instanceType();
if (restp1 != restp)
return PolyType(tparams, restp1);
break;
}
return this;
}
/** Remove all aliases
*/
public Type unalias() {
Type result = unalias(0);//debug
//if (this != result) System.out.println(this + " ==> " + result);//DEBUG
return result;
}
private Type unalias(int n) {
if (n == 100)
throw new Type.Error("alias chain too long (recursive type alias?): " + this);
switch (this) {
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym.kind == ALIAS) return pre.memberInfo(sym).unalias(n + 1);
break;
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) return constr.inst.unalias(n + 1);
else return this;
}
return this;
}
/** The (prefix/argument-adapted) parents of this type.
*/
public Type[] parents() {
switch (unalias()) {
case ThisType(_):
case SingleType(_, _):
return singleDeref().parents();
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym.kind == ALIAS)
return unalias().parents();
else if (sym.kind == CLASS) {
assert sym.typeParams().length == args.length : sym + " " + ArrayApply.toString(args);//debug
return subst(asSeenFrom(sym.info().parents(), pre, sym.owner()),
sym.typeParams(), args);
} else
return new Type[]{sym.info().asSeenFrom(pre, sym.owner())};
case CompoundType(Type[] parts, _):
return parts;
default:
return Type.EMPTY_ARRAY;
}
}
/** Get type parameters of polymorphic method or class
* or EMPTY_ARRAY if not applicable.
*/
public Symbol[] typeParams() {
switch (this) {
case PolyType(Symbol[] tparams, _):
return tparams;
case TypeRef(_, Symbol sym, _):
if (sym.kind == CLASS) return sym.typeParams();
else return sym.info().typeParams();
}
return Symbol.EMPTY_ARRAY;
}
/** Get value parameters of method or class or EMPTY_ARRAY if not
* applicable.
*/
public Symbol[] valueParams() {
switch (this) {
case PolyType(_, Type result):
return result.valueParams();
case MethodType(Symbol[] vparams, _):
return vparams;
case TypeRef(_, Symbol sym, _):
if (sym.kind == CLASS) return sym.valueParams();
else return sym.info().valueParams();
default:
return Symbol.EMPTY_ARRAY;
}
}
/** If this type is a (possibly polymorphic) method type, its result type
* after applying all method argument sections,
* otherwise the type itself.
*/
public Type resultType() {
switch (this) {
case PolyType(_, Type tpe):
return tpe.resultType();
case MethodType(_, Type tpe):
return tpe.resultType();
default:
return this;
}
}
/** The number of value parameter sections of this type.
*/
public int paramSectionCount() {
switch (this) {
case PolyType(_, Type restpe):
return restpe.paramSectionCount();
case MethodType(_, Type restpe):
return restpe.paramSectionCount() + 1;
default: return 0;
}
}
/** The first parameter section of this type.
*/
public Symbol[] firstParams() {
switch (this) {
case PolyType(_, Type restpe):
return restpe.firstParams();
case MethodType(Symbol[] params, _):
return params;
default: return Symbol.EMPTY_ARRAY;
}
}
/** If this type is overloaded, its alternative types,
* otherwise an array consisting of this type itself.
*/
public Type[] alternatives() {
switch (this) {
case OverloadedType(_, Type[] alttypes):
return alttypes;
default:
return new Type[]{this};
}
}
/** If type is a this type of a module class, transform to singletype of
* module.
*/
public Type expandModuleThis() {
switch (this) {
case ThisType(Symbol sym):
if ((sym.flags & MODUL) != 0 && sym.module() != Symbol.NONE) {
return singleType(
sym.owner().thisType().expandModuleThis(), sym.module());
}
}
return this;
}
// Tests --------------------------------------------------------------------
/** Is this type a this type or singleton type?
*/
public boolean isStable() {
switch (unalias()) {
case ThisType(_):
case SingleType(_, _):
return true;
default:
return false;
}
}
/** Is this type a legal prefix?
*/
public boolean isLegalPrefix() {
switch (unalias()) {
case ThisType(_):
case SingleType(_, _):
return true;
case TypeRef(_, Symbol sym, _):
return sym.kind == CLASS &&
((sym.flags & JAVA) != 0 ||
(sym.flags & (TRAIT | ABSTRACTCLASS)) == 0);
default:
return false;
}
}
/** Is this type a reference to an object type?
* todo: replace by this.isSubType(global.definitions.ANY_TYPE)?
*/
public boolean isObjectType() {
switch (unalias()) {
case ThisType(_):
case SingleType(_, _):
case CompoundType(_, _):
return true;
case TypeRef(Type pre, Symbol sym, _):
return sym.kind != ALIAS || unalias().isObjectType();
default:
return false;
}
}
/** Is this type of the form scala.FunctionN[T_1, ..., T_n, +T] or
* scala.Object with scala.FunctionN[T_1, ..., T_n, +T]?
*/
public boolean isFunctionType() {
switch (this) {
case TypeRef(Type pre, Symbol sym, Type[] args):
return sym.fullName().startsWith(Names.scala_Function) &&
args.length > 0;
case CompoundType(Type[] parents, Scope members):
return members.elems == Scope.Entry.NONE &&
parents.length == 2 &&
parents[0].symbol().fullName() == Names.scala_Object &&
parents[1].isFunctionType();
}
return false;
}
// Members and Lookup -------------------------------------------------------
/** Get the scope containing the local members of this type.
* Symbols in this scope are not prefix-adapted!
*/
public Scope members() {
switch (this) {
case ErrorType:
return new Scope();
case TypeRef(_, Symbol sym, _):
return sym.info().members();
case SingleType(_, Symbol sym):
return singleDeref().members();
case CompoundType(Type[] basetypes, Scope members):
return members;
default:
return Scope.EMPTY;
}
}
/** Lookup symbol with given name among all local and inherited members
* of this type; return Symbol.NONE if not found.
*/
public Symbol lookup(Name name) {
switch (this) {
case ErrorType:
return Symbol.ERROR;
case ThisType(_):
case SingleType(_, _):
return singleDeref().lookup(name);
case TypeRef(_, Symbol sym, _):
return sym.info().lookup(name);
case CompoundType(Type[] parts, Scope members):
Symbol sym = members.lookup(name);
if (sym.kind != NONE) return sym;
else return lookupNonPrivate(name);
default:
return Symbol.NONE;
}
}
/** Lookup non-private symbol with given name among all local and
* inherited members of this type; return Symbol.NONE if not found.
*/
public Symbol lookupNonPrivate(Name name) {
return lookupNonPrivate(name, 0);
}
/** Same as before, but with additional parameter `start'.
* If start == 0, lookup in all basetypes of a compound type.
* If start == 1, lookup only in mixin classes.
*/
private Symbol lookupNonPrivate(Name name, int start) {
switch (this) {
case ErrorType:
return Symbol.ERROR;
case ThisType(_):
case SingleType(_, _):
return singleDeref().lookupNonPrivate(name);
case TypeRef(_, Symbol sym, _):
return sym.info().lookupNonPrivate(name, start);
case CompoundType(Type[] parts, Scope members):
Symbol sym = members.lookup(name);
if (sym.kind != NONE && (sym.flags & PRIVATE) == 0)
return sym;
// search base types in reverse; non-abstract members
// take precedence over abstract ones.
int i = parts.length;
sym = Symbol.NONE;
while (i > start && (sym.kind == NONE || (sym.flags & DEFERRED) != 0)) {
i--;
Symbol sym1 = parts[i].lookupNonPrivate(name, i == 0 ? 0 : 1);
if (sym1.kind != NONE &&
(sym1.flags & PRIVATE) == 0 &&
(sym.kind == NONE || (sym1.flags & DEFERRED) == 0))
sym = sym1;
}
return sym;
default:
return Symbol.NONE;
}
}
// Maps --------------------------------------------------------------------------
/** The type of type-to-type functions.
*/
public abstract static class Map {
public abstract Type apply(Type t);
/**
* This method assumes that all symbols in MethodTypes and
* PolyTypes have already been cloned.
*/
public Type applyParams(Type type) {
switch (type) {
case MethodType(Symbol[] vparams, Type result):
map(vparams, true);
Type result1 = applyParams(result);
return result == result1 ? type : MethodType(vparams, result1);
case PolyType(Symbol[] tparams, Type result):
map(tparams, true);
Type result1 = applyParams(result);
return result == result1 ? type : PolyType(tparams, result1);
default:
return apply(type);
}
}
/** Apply map to all top-level components of this type.
*/
public Type map(Type tp) {
switch (tp) {
case ErrorType:
case AnyType:
case NoType:
case UnboxedType(_):
case TypeVar(_, _):
case ThisType(_):
return tp;
case TypeRef(Type pre, Symbol sym, Type[] args):
Type pre1 = apply(pre);
Type[] args1 = map(args);
if (pre1 == pre && args1 == args) return tp;
else return typeRef(pre1, sym, args1);
case SingleType(Type pre, Symbol sym):
Type pre1 = apply(pre);
if (pre1 == pre) return tp;
else return singleType(pre1, sym);
case CompoundType(Type[] parts, Scope members):
Type[] parts1 = map(parts);
Scope members1 = map(members);
if (parts1 == parts && members1 == members) {
return tp;
} else if (members1 == members && !tp.symbol().isCompoundSym()) {
return compoundType(parts1, members, tp.symbol());
} else {
Scope members2 = new Scope();
//Type tp1 = compoundType(parts1, members2);
Type tp1 = (tp.symbol().isCompoundSym()) ? compoundType(parts1, members2)
: compoundType(parts1, members2, tp.symbol());
Symbol[] syms1 = members1.elements();
Symbol[] syms2 = new Symbol[syms1.length];
for (int i = 0; i < syms2.length; i++) {
syms2[i] = syms1[i].cloneSymbol(tp1.symbol());
}
for (int i = 0; i < syms2.length; i++) {
syms2[i].setInfo(syms1[i].info().subst(syms1, syms2));
if (syms2[i].kind == TYPE)
syms2[i].setLoBound(syms1[i].loBound().subst(syms1, syms2));
}
for (int i = 0; i < syms2.length; i++) {
members2.enter(syms2[i]);
}
return tp1;
}
case MethodType(Symbol[] vparams, Type result):
Symbol[] vparams1 = map(vparams);
Type result1 = apply(result);
if (vparams1 == vparams && result1 == result) return tp;
else return MethodType(vparams1, result1);
case PolyType(Symbol[] tparams, Type result):
Symbol[] tparams1 = map(tparams);
Type result1 = apply(result);
if (tparams1 != tparams) result1 = result1.subst(tparams, tparams1);
if (tparams1 == tparams && result1 == result) return tp;
else return PolyType(tparams1, result1);
case OverloadedType(Symbol[] alts, Type[] alttypes):
Type[] alttypes1 = map(alttypes);
if (alttypes1 == alttypes) return tp;
else return OverloadedType(alts, alttypes1);
case UnboxedArrayType(Type elemtp):
Type elemtp1 = apply(elemtp);
if (elemtp1 == elemtp) return tp;
else return UnboxedArrayType(elemtp1);
default:
throw new ApplicationError(tp + " " + tp.symbol());
}
}
public final Symbol map(Symbol sym) {
return map(sym, false);
}
public Symbol map(Symbol sym, boolean dontClone) {
Type tp = sym.info();
Type tp1 = apply(tp);
if (tp != tp1) {
if (!dontClone) sym = sym.cloneSymbol();
sym.setInfo(tp1);
dontClone = true;
}
if (sym.kind == TYPE) {
Type lb = sym.loBound();
Type lb1 = apply(lb);
if (lb != lb1) {
if (!dontClone) sym = sym.cloneSymbol();
sym.setLoBound(lb1);
}
}
return sym;
}
public Type[] map(Type[] tps) {
Type[] tps1 = tps;
for (int i = 0; i < tps.length; i++) {
Type tp = tps[i];
Type tp1 = apply(tp);
if (tp1 != tp && tps1 == tps) {
tps1 = new Type[tps.length];
System.arraycopy(tps, 0, tps1, 0, i);
}
tps1[i] = tp1;
}
return tps1;
}
/** Apply map to all elements of this array of symbols,
* preserving recursive references to symbols in the array.
*/
public final Symbol[] map(Symbol[] syms) {
return map(syms, false);
}
public Symbol[] map(Symbol[] syms, boolean dontClone) {
Symbol[] syms1 = syms;
for (int i = 0; i < syms.length; i++) {
Symbol sym = syms[i];
Symbol sym1 = map(sym, dontClone);
if (sym != sym1 && syms1 == syms) {
syms1 = new Symbol[syms.length];
System.arraycopy(syms, 0, syms1, 0, i);
}
syms1[i] = sym1;
}
if (syms1 != syms) {
for (int i = 0; i < syms1.length; i++) {
if (syms1[i] == syms[i])
syms1[i] = syms[i].cloneSymbol();
}
new SubstSymMap(syms, syms1).map(syms1, true);
}
return syms1;
}
/** Apply map to all elements of this array of this scope.
*/
public Scope map(Scope s) {
Symbol[] members = s.elements();
Symbol[] members1 = map(members);
if (members == members1) return s;
else return new Scope(members1);
}
}
public abstract static class MapOnlyTypes extends Map {
public Symbol map(Symbol sym, boolean dontClone) { return sym; }
public Symbol[] map(Symbol[] syms, boolean dontClone) { return syms; }
public Scope map(Scope s) { return s; }
}
// baseType and asSeenFrom --------------------------------------------------------
/** Return the base type of this type whose symbol is `clazz', or NoType, if
* such a type does not exist.
*/
public Type baseType(Symbol clazz) {
//System.out.println(this + ".baseType(" + clazz + ")");//DEBUG
switch (this) {
case ErrorType:
return ErrorType;
case ThisType(_):
case SingleType(_, _):
return singleDeref().baseType(clazz);
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym == clazz)
return this;
else if (sym.kind == TYPE || sym.kind == ALIAS)
return pre.memberInfo(sym).baseType(clazz);
else if (clazz.isCompoundSym())
return NoType;
else {
return sym.baseType(clazz)
.asSeenFrom(pre, clazz.owner())
.subst(sym.typeParams(), args);
}
case CompoundType(Type[] parts, _):
for (int i = parts.length - 1; i >= 0; i--) {
Type result = parts[i].baseType(clazz);
if (result != NoType) return result;
}
break;
case UnboxedArrayType(_):
if (clazz == Global.instance.definitions.ANY_CLASS ||
clazz == Global.instance.definitions.ANYREF_CLASS)
return clazz.type();
}
return NoType;
}
/** Return overriding instance of `sym' in this type,
* or `sym' itself if none exists.
*/
public Symbol rebind(Symbol sym) {
Symbol sym1 = lookupNonPrivate(sym.name);
if (sym1.kind != NONE) {
//System.out.println("rebinding " + sym + " to " + sym1);//DEBUG
return sym1;
}
else return sym;
}
/** A map to implement `asSeenFrom'.
*/
static class AsSeenFromMap extends Map {
private Type pre;
private Symbol clazz;
AsSeenFromMap(Type pre, Symbol clazz) {
this.pre = pre; this.clazz = clazz;
}
public Type apply(Type t) {
if (pre == NoType || clazz.kind != CLASS)
return t;
switch (t) {
case ThisType(Symbol sym):
return t.toPrefix(sym, pre, clazz);
case TypeRef(Type prefix, Symbol sym, Type[] args):
if (sym.kind == ALIAS) {
return apply(t.unalias());
} else if (sym.owner().isPrimaryConstructor()) {
assert sym.kind == TYPE;
Type t1 = t.toInstance(sym, pre, clazz);
//System.out.println(t + ".toInstance(" + pre + "," + clazz + ") = " + t1);//DEBUG
return t1;
} else {
Type prefix1 = apply(prefix);
Symbol sym1 = (prefix1 == prefix || (sym.flags & MODUL) != 0)
? sym : prefix1.rebind(sym);
Type[] args1 = map(args);
if (prefix1 == prefix && args1 == args) return t;
else return typeRef(prefix1, sym1, args1);
}
case SingleType(Type prefix, Symbol sym):
try {
Type prefix1 = apply(prefix);
if (prefix1 == prefix) return t;
else return singleType(prefix1, prefix1.rebind(sym));
} catch (Type.Error ex) {}
return apply(t.singleDeref());
default:
return map(t);
}
}
}
//where
Type toInstance(Symbol sym, Type pre, Symbol clazz) {
if (pre == NoType || clazz.kind != CLASS)
return this;
Symbol ownclass = sym.owner().primaryConstructorClass();
if (ownclass == clazz &&
pre.widen().symbol().isSubClass(ownclass)) {
switch (pre.baseType(ownclass)) {
case TypeRef(_, Symbol basesym, Type[] baseargs):
Symbol[] baseparams = basesym.typeParams();
for (int i = 0; i < baseparams.length; i++) {
if (sym == baseparams[i]) return baseargs[i];
}
//System.out.println(sym + " " + basesym + " " + ArrayApply.toString(baseparams));//DEBUG
break;
case ErrorType:
return ErrorType;
}
throw new ApplicationError(
this + " in " + ownclass + " cannot be instantiated from " + pre.widen()
);
} else {
return toInstance(sym, pre.baseType(clazz).prefix(), clazz.owner());
}
}
Type toPrefix(Symbol sym, Type pre, Symbol clazz) {
if (pre == NoType || clazz.kind != CLASS)
return this;
else if (sym.isSubClass(clazz) &&
pre.widen().symbol().isSubClass(sym))
return pre;
else
return toPrefix(sym, pre.baseType(clazz).prefix(), clazz.owner());
}
/** This type as seen from prefix `pre' and class `clazz'. This means:
* Replace all thistypes of `clazz' or one of its superclasses by `pre'
* and instantiate all parameters by arguments of `pre'.
* Proceed analogously for thistypes referring to outer classes.
*/
public Type asSeenFrom(Type pre, Symbol clazz) {
//System.out.println("computing asseenfrom of " + this + " with " + pre + "," + clazz);//DEBUG
return new AsSeenFromMap(pre, clazz).apply(this);
}
/** Types `these' as seen from prefix `pre' and class `clazz'.
*/
public static Type[] asSeenFrom(Type[] these, Type pre, Symbol clazz) {
return new AsSeenFromMap(pre, clazz).map(these);
}
/** The info of `sym', seen as a member of this type.
*/
public Type memberInfo(Symbol sym) {
return sym.info().asSeenFrom(this, sym.owner());
}
/** The type of `sym', seen as a member of this type.
*/
public Type memberType(Symbol sym) {
return sym.type().asSeenFrom(this, sym.owner());
}
/** The low bound of `sym', seen as a member of this type.
*/
public Type memberLoBound(Symbol sym) {
return sym.loBound().asSeenFrom(this, sym.owner());
}
// Substitutions ---------------------------------------------------------------
/** A common map superclass for symbol/symbol and type/symbol substitutions.
*/
public static abstract class SubstMap extends Map {
private Symbol[] from;
SubstMap(Symbol[] from) {
this.from = from;
}
public boolean matches(Symbol sym1, Symbol sym2) {
return sym1 == sym2;
}
/** Produce replacement type
* @param i The index in `from' of the symbol to be replaced.
* @param fromtp The type referring to this symbol.
*/
protected abstract Type replacement(int i, Type fromtp);
/** Produce new substitution where some symbols are excluded.
* @param newfrom The new array of from symbols (without excluded syms)
* @param excluded The array of excluded sysmbols
*/
protected abstract SubstMap exclude(Symbol[] newfrom, Symbol[] excluded);
public Type apply(Type t) {
switch (t) {
case TypeRef(ThisType(_), Symbol sym, Type[] args):
for (int i = 0; i < from.length; i++) {
if (matches(sym, from[i])) return replacement(i, t);
}
break;
case SingleType(ThisType(_), Symbol sym):
for (int i = 0; i < from.length; i++) {
if (matches(sym, from[i])) return replacement(i, t);
}
break;
case PolyType(Symbol[] tparams, Type result):
Symbol[] from1 = excludeSyms(from, tparams, from);
if (from1 != from) {
SubstMap f = exclude(from1, tparams);
Symbol[] tparams1 = f.map(tparams);
Type result1 = f.apply(result);
if (tparams1 != tparams)
result1 = result1.subst(tparams, tparams1);
if (tparams1 == tparams && result1 == result) return t;
else return PolyType(tparams1, result1);
}
}
return map(t);
}
//where
private boolean contains1(Symbol[] syms, Symbol sym) {
int i = 0;
while (i < syms.length && syms[i] != sym) i++;
return i < syms.length;
}
private int nCommon(Symbol[] from, Symbol[] tparams) {
int cnt = 0;
for (int i = 0; i < from.length; i++) {
if (contains1(tparams, from[i])) cnt++;
}
return cnt;
}
private Symbol[] excludeSyms(Symbol[] from, Symbol[] tparams, Symbol[] syms) {
int n = nCommon(from, tparams);
if (n == 0) {
return syms;
} else {
Symbol[] syms1 = new Symbol[syms.length - n];
int j = 0;
for (int i = 0; i < from.length; i++) {
if (!contains1(tparams, from[i])) syms1[j++] = syms[i];
}
return syms1;
}
}
private Type[] excludeTypes(Symbol[] from, Symbol[] tparams, Type[] types) {
int n = nCommon(from, tparams);
if (n == 0) {
return types;
} else {
Type[] types1 = new Type[types.length - n];
int j = 0;
for (int i = 0; i < from.length; i++) {
if (!contains1(tparams, from[i])) types1[j++] = types[i];
}
return types1;
}
}
}
/** A map for symbol/symbol substitutions
*/
public static class SubstSymMap extends SubstMap {
Symbol[] to;
protected SubstSymMap(Symbol[] from, Symbol[] to) {
super(from);
this.to = to;
}
protected Type replacement(int i, Type fromtp) {
switch (fromtp) {
case TypeRef(Type pre, Symbol sym, Type[] args):
return typeRef(pre, to[i], args);
case SingleType(Type pre, Symbol sym):
return singleType(pre, to[i]);
default:
throw new ApplicationError();
}
}
protected SubstMap exclude(Symbol[] newfrom, Symbol[] excluded) {
return new SubstSymMap(newfrom, excludeSyms(from, excluded, to));
}
}
/** A map for type/symbol substitutions
*/
public static class SubstTypeMap extends SubstMap {
Type[] to;
protected SubstTypeMap(Symbol[] from, Type[] to) {
super(from);
this.to = to;
}
protected Type replacement(int i, Type fromtp) {
return to[i];
}
protected SubstMap exclude(Symbol[] newfrom, Symbol[] excluded) {
return new SubstTypeMap(newfrom, excludeTypes(from, excluded, to));
}
}
/** Substitute symbols `to' for occurrences of symbols `from' in this type.
*/
public Type subst(Symbol[] from, Symbol[] to) {
assert from.length == to.length
: this + ": " + from.length + " != " + to.length;
if (from.length != 0 && from != to)
return new SubstSymMap(from, to).apply(this);
else return this;
}
/** Substitute symbols `to' for occurrences of symbols `from' in these types.
*/
public static Type[] subst(Type[] these, Symbol[] from, Symbol[] to) {
assert from.length == to.length;
if (these.length != 0 && from.length != 0 && from != to)
return new SubstSymMap(from, to).map(these);
else return these;
}
/** Substitute types `to' for occurrences of symbols `from' in this type.
*/
public Type subst(Symbol[] from, Type[] to) {
assert from.length == to.length
: this + ": " + Debug.show(from) + " <> " + ArrayApply.toString(to);
if (from.length != 0)
return new SubstTypeMap(from, to).apply(this);
else return this;
}
/** Substitute types `to' for occurrences of symbols `from' in these types.
*/
public static Type[] subst(Type[] these, Symbol[] from, Type[] to) {
assert from.length == to.length;
if (these.length != 0 && from.length != 0)
return new SubstTypeMap(from, to).map(these);
else return these;
}
/** A map for substitutions of thistypes.
*/
public static class SubstThisMap extends Map {
Symbol from;
Type to;
public SubstThisMap(Symbol from, Type to) {
this.from = from;
this.to = to;
}
public SubstThisMap(Symbol oldSym, Symbol newSym) {
this(oldSym, newSym.thisType());
}
public Type apply(Type t) {
switch (t) {
case ThisType(Symbol sym):
if (sym == from) return to;
else return t;
default:
return map(t);
}
}
}
public Type substThis(Symbol from, Type to) {
return new SubstThisMap(from, to).apply(this);
}
public static Type[] substThis(Type[] these, Symbol from, Type to) {
return new SubstThisMap(from, to).map(these);
}
static class ContainsMap extends Map {
boolean result = false;
Symbol sym;
ContainsMap(Symbol sym) {
this.sym = sym;
}
public Type apply(Type t) {
if (!result) {
switch (t) {
case TypeRef(Type pre, Symbol sym1, Type[] args):
if (sym == sym1) result = true;
else { map(pre); map(args); }
break;
case SingleType(Type pre, Symbol sym1):
map(pre);
if (sym == sym1) result = true;
break;
default:
map(t);
}
}
return t;
}
}
/** Does this type contain symbol `sym'?
*/
public boolean contains(Symbol sym) {
ContainsMap f = new ContainsMap(sym);
f.apply(this);
return f.result;
}
/** Does this type contain any of the symbols `syms'?
*/
public boolean containsSome(Symbol[] syms) {
for (int i = 0; i < syms.length; i++)
if (contains(syms[i])) return true;
return false;
}
// Cloning ---------------------------------------------------------------
/**
* Clones a type i.e. returns a new type "as seen from" the new
* owner and where all symbols in MethodTypes and PolyTypes have
* been cloned.
*/
public Type cloneType(Symbol oldOwner, Symbol newOwner) {
Type clone = cloneType0(oldOwner, newOwner);
if (oldOwner != newOwner && oldOwner.isClass())
clone = new SubstThisMap(oldOwner, newOwner).applyParams(clone);
return clone;
}
private Type cloneType0(Symbol oldOwner, Symbol newOwner) {
switch (this) {
case MethodType(Symbol[] vparams, Type result):
Symbol[] clones = new Symbol[vparams.length];
for (int i = 0; i < clones.length; i++) {
assert vparams[i].owner() == oldOwner : Debug.show(vparams[i]);
clones[i] = vparams[i].cloneSymbol(newOwner);
}
result = result.cloneType0(oldOwner, newOwner);
Type clone = Type.MethodType(clones, result);
if (vparams.length != 0)
clone = new SubstSymMap(vparams, clones).applyParams(clone);
return clone;
case PolyType(Symbol[] tparams, Type result):
Symbol[] clones = new Symbol[tparams.length];
for (int i = 0; i < clones.length; i++) {
assert tparams[i].owner() == oldOwner : Debug.show(tparams[i]);
clones[i] = tparams[i].cloneSymbol(newOwner);
}
result = result.cloneType0(oldOwner, newOwner);
Type clone = Type.PolyType(clones, result);
if (tparams.length != 0)
clone = new SubstSymMap(tparams, clones).applyParams(clone);
return clone;
default:
return this;
}
}
// Comparisons ------------------------------------------------------------------
/** Is this type a subtype of that type?
*/
public boolean isSubType(Type that) {
if (explainSwitch) {
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(this + " < " + that + "?");
indent++;
}
boolean result = isSubType0(that);
if (explainSwitch) {
indent--;
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(result);
}
return result;
}
public boolean isSubType0(Type that) {
if (this == that) return true;
switch (this) {
case ErrorType:
case AnyType:
return true;
}
switch (that) {
case ErrorType:
case AnyType:
return true;
case NoType:
return false;
case ThisType(_):
case SingleType(_, _):
switch (this) {
case ThisType(_):
case SingleType(_, _):
return this.isSameAs(that);
}
break;
case TypeRef(Type pre1, Symbol sym1, Type[] args1):
switch (this) {
case TypeRef(Type pre, Symbol sym, Type[] args):
boolean samepre = pre.isSameAs(pre1);
if ((samepre && sym == sym1 /* fast case */ ||
!samepre && pre.isSubType(pre1) && sym == pre.rebind(sym1)) &&
isSubArgs(args, args1, sym.typeParams())
||
sym.kind == TYPE && pre.memberInfo(sym).isSubType(that))
return true;
break;
}
if (sym1.kind == CLASS) {
Type base = this.baseType(sym1);
if (this != base && base.isSubType(that))
return true;
}
break;
case CompoundType(Type[] parts1, Scope members1):
int i = 0;
while (i < parts1.length && isSubType(parts1[i])) i++;
if (i == parts1.length && specializes(members1))
return true;
break;
case MethodType(Symbol[] ps1, Type res1):
switch (this) {
case MethodType(Symbol[] ps, Type res):
if (ps.length != ps1.length) return false;
for (int i = 0; i < ps.length; i++) {
Symbol p1 = ps1[i];
Symbol p = ps[i];
if (!p1.type().isSubType(p.type()) ||
(p1.flags & (Modifiers.DEF | Modifiers.REPEATED)) !=
(p.flags & (Modifiers.DEF | Modifiers.REPEATED)))
return false;
}
return res.isSubType(res1);
}
break;
case PolyType(Symbol[] ps1, Type res1):
switch (this) {
case PolyType(Symbol[] ps, Type res):
if (ps.length != ps1.length) return false;
for (int i = 0; i < ps.length; i++)
if (!ps1[i].info().subst(ps1, ps).isSubType(ps[i].info()) ||
!ps[i].loBound().isSubType(ps1[i].loBound().subst(ps1, ps)))
return false;
return res.isSubType(res1.subst(ps1, ps));
}
break;
case OverloadedType(Symbol[] alts1, Type[] alttypes1):
for (int i = 0; i < alttypes1.length; i++) {
if (!isSubType(alttypes1[i]))
return false;
}
return true;
case UnboxedType(int tag1):
switch (this) {
case UnboxedType(int tag):
return tag == tag1 ||
(tag < tag1 && tag1 <= DOUBLE && tag1 != CHAR);
}
break;
case UnboxedArrayType(UnboxedType(int tag1)):
switch (this) {
case UnboxedArrayType(UnboxedType(int tag)):
return tag1 == tag;
}
break;
case UnboxedArrayType(Type elemtp1):
switch (this) {
case UnboxedArrayType(Type elemtp):
return elemtp.isSubType(elemtp1);
}
break;
case TypeVar(Type origin, Constraint constr):
//todo: should we test for equality with origin?
if (constr.inst != NoType) {
return this.isSubType(constr.inst);
} else {
constr.lobounds = new List(this, constr.lobounds);
return true;
}
default:
throw new ApplicationError(this + " <: " + that);
}
switch (this) {
case NoType:
return false;
case ThisType(_):
case SingleType(_, _):
if (this.singleDeref().isSubType(that)) return true;
break;
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) {
return constr.inst.isSubType(that);
} else {
constr.hibounds = new List(that, constr.hibounds);
return true;
}
case TypeRef(_, Symbol sym, _):
switch (that) {
case TypeRef(Type pre1, Symbol sym1, _):
if (sym1.kind == TYPE && this.isSubType(that.loBound()))
return true;
}
if (sym.kind == ALIAS)
return this.unalias().isSubType(that);
else if (sym == Global.instance.definitions.ALL_CLASS)
return that.isSubType(Global.instance.definitions.ANY_TYPE);
else if (sym == Global.instance.definitions.ALLREF_CLASS)
return
that.symbol() == Global.instance.definitions.ANY_CLASS ||
(that.symbol() != Global.instance.definitions.ALL_CLASS &&
that.isSubType(Global.instance.definitions.ANYREF_TYPE));
break;
case OverloadedType(Symbol[] alts, Type[] alttypes):
for (int i = 0; i < alttypes.length; i++) {
if (alttypes[i].isSubType(that)) return true;
}
break;
}
switch (that) {
case TypeRef(_, Symbol sym1, _):
if (sym1.kind == ALIAS) return this.isSubType(that.unalias());
break;
}
return false;
}
/** Are types `these' subtypes of corresponding types `those'?
*/
public static boolean isSubType(Type[] these, Type[] those) {
if (these.length != those.length) return false;
for (int i = 0; i < these.length; i++) {
if (!these[i].isSubType(those[i])) return false;
}
return true;
}
/** Are types `these' arguments types conforming to corresponding types `those'?
*/
static boolean isSubArgs(Type[] these, Type[] those, Symbol[] tparams) {
if (these.length != those.length) return false;
for (int i = 0; i < these.length; i++) {
if ((tparams[i].flags & COVARIANT) != 0) {
if (!these[i].isSubType(those[i])) return false;
} else if ((tparams[i].flags & CONTRAVARIANT) != 0) {
//System.out.println("contra: " + these[i] + " " + those[i] + " " + those[i].isSubType(these[i]));//DEBUG
if (!those[i].isSubType(these[i])) return false;
} else {
if (!these[i].isSameAs(those[i])) return false;
}
}
return true;
}
public static boolean isSubSet(Type[] alts, Type[] alts1) {
for (int i = 0; i < alts.length; i++) {
int j = 0;
while (j < alts1.length && !alts1[j].isSameAs(alts[i])) j++;
if (j == alts1.length) return false;
}
return true;
}
/** Does this type implement all symbols in scope `s' with same or stronger types?
*/
public boolean specializes(Scope s) {
for (Scope.Entry e = s.elems; e != Scope.Entry.NONE; e = e.next)
if (!specializes(e.sym)) return false;
return true;
}
/** Does this type implement symbol `sym1' with same or stronger type?
*/
public boolean specializes(Symbol sym1) {
if (explainSwitch) {
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(this + " specializes " + sym1 + "?");
indent++;
}
boolean result = specializes0(sym1);
if (explainSwitch) {
indent--;
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(result);
}
return result;
}
public boolean specializes0(Symbol sym1) {
Symbol sym = lookup(sym1.name);
Type self = narrow();
Symbol[] tparams = symbol().typeParams();
Type[] targs = typeArgs();
return
sym == sym1
||
(sym.kind == sym1.kind || sym1.kind == TYPE) &&
self.memberInfo(sym).subst(tparams, targs)
.isSubType(sym1.info().substThis(sym.owner(), self)) &&
sym1.loBound().substThis(sym.owner(), self)
.isSubType(self.memberLoBound(sym).subst(tparams, targs))
||
(sym.kind == TYPE && sym1.kind == ALIAS &&
sym1.info().unalias().isSameAs(sym.type()));
}
/** Is this type the same as that type?
*/
public boolean isSameAs(Type that) {
if (explainSwitch) {
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(this + " = " + that + "?");
indent++;
}
boolean result = isSameAs0(that);
if (explainSwitch) {
indent--;
for (int i = 0; i < indent; i++) System.out.print(" ");
System.out.println(result);
}
return result;
}
public boolean isSameAs0(Type that) {
if (this == that) return true;
switch (this) {
case ErrorType:
case AnyType:
return true;
case ThisType(Symbol sym):
switch (that) {
case ThisType(Symbol sym1):
return sym == sym1;
case SingleType(Type pre1, Symbol sym1):
return sym1.isModule()
&& sym == sym1.moduleClass()
&& sym.owner().thisType().isSameAs(pre1)
||
deAlias(that) != that &&
this.isSameAs(deAlias(that));
}
break;
case SingleType(Type pre, Symbol sym):
switch (that) {
case SingleType(Type pre1, Symbol sym1):
return sym == sym1 && pre.isSameAs(pre1)
||
(deAlias(this) != this || deAlias(that) != that) &&
deAlias(this).isSameAs(deAlias(that));
case ThisType(Symbol sym1):
return sym.isModule()
&& sym.moduleClass() == sym1
&& pre.isSameAs(sym1.owner().thisType())
||
deAlias(this) != this &&
deAlias(this).isSameAs(that);
}
break;
case TypeRef(Type pre, Symbol sym, Type[] args):
switch (that) {
case TypeRef(Type pre1, Symbol sym1, Type[] args1):
if (sym == sym1 && pre.isSameAs(pre1) && isSameAs(args, args1))
return true;
}
break;
case CompoundType(Type[] parts, Scope members):
switch (that) {
case CompoundType(Type[] parts1, Scope members1):
if (parts.length != parts1.length) return false;
for (int i = 0; i < parts.length; i++)
if (!parts[i].isSameAs(parts1[i])) return false;
return isSameAs(members, members1);
}
break;
case MethodType(Symbol[] ps, Type res):
switch (that) {
case MethodType(Symbol[] ps1, Type res1):
if (ps.length != ps1.length) return false;
for (int i = 0; i < ps.length; i++) {
Symbol p1 = ps1[i];
Symbol p = ps[i];
if (!p1.type().isSameAs(p.type()) ||
(p1.flags & (Modifiers.DEF | Modifiers.REPEATED)) !=
(p.flags & (Modifiers.DEF | Modifiers.REPEATED)))
return false;
}
return res.isSameAs(res1);
}
break;
case PolyType(Symbol[] ps, Type res):
switch (that) {
case PolyType(Symbol[] ps1, Type res1):
if (ps.length != ps1.length) return false;
for (int i = 0; i < ps.length; i++)
if (!ps1[i].info().subst(ps1, ps).isSameAs(ps[i].info()) ||
!ps1[i].loBound().subst(ps1, ps).isSameAs(ps[i].loBound()))
return false;
return res.isSameAs(res1.subst(ps1, ps));
}
break;
case OverloadedType(Symbol[] alts, Type[] alttypes):
switch (that) {
case OverloadedType(Symbol[] alts1, Type[] alttypes1):
return isSubSet(alttypes1, alttypes)
&& isSubSet(alttypes, alttypes1);
}
break;
case UnboxedType(int kind):
switch (that) {
case UnboxedType(int kind1):
return kind == kind1;
}
break;
case UnboxedArrayType(Type elemtp):
switch (that) {
case UnboxedArrayType(Type elemtp1):
return elemtp.isSameAs(elemtp1);
}
break;
}
switch (that) {
case ErrorType:
case AnyType:
return true;
case NoType:
return false;
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) return constr.inst.isSameAs(this);
else return constr.instantiate(this.any2typevar());
}
switch (this) {
case NoType:
return false;
case TypeRef(_, Symbol sym, _):
if (sym.kind == ALIAS) return this.unalias().isSameAs(that);
break;
case TypeVar(Type origin, Constraint constr):
if (constr.inst != NoType) return constr.inst.isSameAs(that);
else return constr.instantiate(that.any2typevar());
}
switch (that) {
case TypeRef(_, Symbol sym, _):
if (sym.kind == ALIAS) return this.isSameAs(that.unalias());
}
return false;
}
//where
Type deAlias(Type tp) {
switch (tp) {
case SingleType(_, _):
Type tp1 = tp.singleDeref();
if (tp1.isStable()) return deAlias(tp1);
}
return tp;
}
/** Are types `these' the same as corresponding types `those'?
*/
public static boolean isSameAs(Type[] these, Type[] those) {
if (these.length != those.length) return false;
for (int i = 0; i < these.length; i++) {
if (!these[i].isSameAs(those[i])) return false;
}
return true;
}
/** Do scopes `s1' and `s2' define he same symbols with the same kinds and infos?
*/
public boolean isSameAs(Scope s1, Scope s2) {
return isSubScope(s1, s2) && isSubScope(s2, s1);
}
/** Does scope `s1' define all symbols of scope `s2' with the same kinds and infos?
*/
private boolean isSubScope(Scope s1, Scope s2) {
for (Scope.Entry e = s2.elems; e != Scope.Entry.NONE; e = e.next) {
Symbol sym2 = e.sym;
Symbol sym1 = s1.lookup(sym2.name);
if (sym1.kind != sym2.kind ||
!sym1.info().isSameAs(
sym2.info().substThis(
sym2.owner(), sym1.owner().thisType())) ||
!sym1.loBound().isSameAs(
sym2.loBound().substThis(
sym2.owner(), sym1.owner().thisType())))
return false;
}
return true;
}
boolean isSameAsAll(Type[] tps) {
int i = 1;
while (i < tps.length && isSameAs(tps[i])) i++;
return i == tps.length;
}
/** Map every occurrence of AnyType to a fresh type variable.
*/
public static Map any2typevarMap = new Map() {
public Type apply(Type t) { return t.any2typevar(); }
};
public Type any2typevar() {
switch (this) {
case AnyType:
return TypeVar(this, new Constraint());
default:
return any2typevarMap.map(this);
}
}
// Closures and Least Upper Bounds ---------------------------------------------------
/** The closure of this type, i.e. the widened type itself followed by all
* its direct and indirect (pre-) base types, sorted by Symbol.isLess().
*/
public Type[] closure() {
switch (this.widen().unalias()) {
case TypeRef(Type pre, Symbol sym, Type[] args):
return subst(
asSeenFrom(sym.closure(), pre, sym.owner()),
sym.typeParams(), args);
case CompoundType(Type[] parts, Scope members):
Type[][] closures = new Type[parts.length][];
for (int i = 0; i < parts.length; i++)
closures[i] = parts[i].closure();
return union(closures);
default:
return new Type[]{this};
}
}
/** return union of array of closures. It is assumed that
* for any two base types with the same class symbols the later one
* is a subtype of the former.
*/
static private Type[] union(Type[][] closures) {
if (closures.length == 1) return closures[0]; // fast special case
int[] index = new int[closures.length];
int totalsize = 0;
for (int i = 0; i < index.length; i++) {
index[i] = 0;
totalsize = totalsize + closures[i].length;
}
Type[] res = new Type[totalsize];
int j = 0;
while (true) {
// find minimal element
Type min = null;
for (int i = 0; i < index.length; i++) {
if (index[i] < closures[i].length) {
Type cltype = closures[i][index[i]];
if (min == null ||
cltype.symbol().isLess(min.symbol()) ||
cltype.symbol() == min.symbol()) {
min = cltype;
}
}
}
if (min == null) break;
res[j] = min;
j = j + 1;
// bump all indices that start with minimal element
for (int i = 0; i < index.length; i++) {
if (index[i] < closures[i].length &&
closures[i][index[i]].symbol() == min.symbol())
index[i] = index[i] + 1;
}
}
Type[] result = new Type[j];
System.arraycopy(res, 0, result, 0, j);
return result;
}
/** return intersection of non-empty array of closures
*/
static private Type[] intersection(Type[][] closures) {
if (closures.length == 1) return closures[0]; // fast special case
int[] index = new int[closures.length];
Type[] mintypes = new Type[closures.length];
int minsize = Integer.MAX_VALUE;
for (int i = 0; i < index.length; i++) {
index[i] = 0;
if (closures[i].length < minsize) minsize = closures[i].length;
}
Type[] res = new Type[minsize];
int j = 0;
L:
while (true) {
// find minimal element
Symbol minsym = null;
for (int i = 0; i < index.length; i++) {
if (index[i] == closures[i].length) break L;
Symbol clsym = closures[i][index[i]].symbol();
if (minsym == null || clsym.isLess(minsym)) minsym = clsym;
}
boolean agree = true;
// bump all indices that start with minimal element
for (int i = 0; i < index.length; i++) {
Type cltype = closures[i][index[i]];
if (cltype.symbol() == minsym) {
mintypes[i] = cltype;
index[i] = index[i] + 1;
} else {
agree = false;
}
}
if (agree) {
Type mintype = argLub(mintypes);
if (mintype.symbol().kind == CLASS) {
res[j] = mintype;
j = j + 1;
}
}
}
Type[] result = new Type[j];
System.arraycopy(res, 0, result, 0, j);
return result;
}
/** same as lub, but all types are instances of the same class,
* possibly with different prefixes and arguments.
*/
//todo: catch lubs not within bounds.
static Type argLub(Type[] tps) {
tps = elimRedundant(tps, true);
if (tps.length == 1) return tps[0];
Type pre = tps[0].prefix();
Symbol sym = tps[0].symbol();
Symbol[] tparams = sym.typeParams();
Type[] args = new Type[tparams.length];
Type[][] argss = new Type[args.length][tps.length];
for (int i = 0; i < tps.length; i++) {
switch (tps[i]) {
case TypeRef(Type pre1, Symbol sym1, Type[] args1):
assert sym == sym1;
assert args1.length == args.length;
if (!pre.isSameAs(pre1)) return NoType;
for (int j = 0; j < args1.length; j++)
argss[j][i] = args1[j];
break;
case ErrorType:
return ErrorType;
default:
assert false : tps[i];
}
}
for (int j = 0; j < args.length; j++) {
if ((tparams[j].flags & COVARIANT) != 0)
args[j] = lub(argss[j]);
else if ((tparams[j].flags & CONTRAVARIANT) != 0)
args[j] = glb(argss[j]);
else return NoType;
}
return typeRef(pre, sym, args);
}
/** The frontier of a closure C is the minimal set of types such that
* the union of the closures of these types equals C.
*/
static private Type[] frontier(Type[] closure) {
Type[] front = new Type[closure.length];
int j = 0;
for (int i = 0; i < closure.length; i++) {
int k = 0;
Type tp = closure[i];
while (k < j && !front[k].symbol().isSubClass(tp.symbol()))
k++;
if (k == j) {
front[j] = tp;
j++;
}
}
Type[] result = new Type[j];
System.arraycopy(front, 0, result, 0, j);
return result;
}
/** remove types that are subtypes of some other type.
*/
static private Type[] elimRedundant(Type[] tps, boolean elimLower) {
Type.List tl = Type.List.EMPTY;
int nredundant = 0;
boolean[] redundant = new boolean[tps.length];
for (int i = 0; i < tps.length; i++) {
if (tps[i] == ErrorType) {
return new Type[]{ErrorType};
} else {
assert tps[i].isObjectType() : tps[i];
for (int j = 0; j < i && !redundant[i]; j++) {
if (!redundant[j]) {
if (tps[i].isSubType(tps[j])) {
redundant[elimLower ? i : j] = true;
nredundant++;
} else if (tps[j].isSubType(tps[i])) {
redundant[elimLower ? j : i] = true;
nredundant++;
}
}
}
}
}
if (nredundant != 0) {
Type[] tps1 = new Type[tps.length - nredundant];
int n = 0;
for (int i = 0; i < tps.length; i++) {
if (!redundant[i]) tps1[n++] = tps[i];
}
return tps1;
} else {
return tps;
}
}
/** Return the least upper bound of non-empty array of types `tps'.
*/
public static Type lub(Type[] tps) {
//System.out.println("lub" + ArrayApply.toString(tps));//DEBUG
if (tps.length == 0) return Global.instance.definitions.ALL_TYPE;
// remove types that are subtypes of some other type.
tps = elimRedundant(tps, true);
if (tps.length == 1) return tps[0];
// intersect closures and build frontier.
Type[][] closures = new Type[tps.length][];
for (int i = 0; i < tps.length; i++) {
closures[i] = tps[i].closure();
}
Type[] allBaseTypes = intersection(closures);
Type[] leastBaseTypes = frontier(allBaseTypes);
assert leastBaseTypes.length > 0 : ArrayApply.toString(tps);
// add refinements where necessary
Scope members = new Scope();
Type lubType = compoundType(leastBaseTypes, members);
Type lubThisType = lubType.narrow();
//System.out.println("lubtype = " + lubType);//DEBUG
Symbol[] rsyms = new Symbol[tps.length];
Type[] rtps = new Type[tps.length];
Type[] rlbs = new Type[tps.length];
for (int i = 0; i < allBaseTypes.length; i++) {
for (Scope.Entry e = allBaseTypes[i].members().elems;
e != Scope.Entry.NONE;
e = e.next) {
Name name = e.sym.name;
if ((e.sym.flags & PRIVATE) == 0 && lubType.lookup(name) == e.sym) {
Type symType = memberTp(lubThisType, e.sym);
Type symLoBound = lubThisType.memberLoBound(e.sym);
int j = 0;
while (j < tps.length) {
rsyms[j] = tps[j].lookupNonPrivate(name);
if (rsyms[j] == e.sym) break;
if (rsyms[j].isMethod()) break; // since methods cannot
// appear in refinements.
rtps[j] = memberTp(tps[j], rsyms[j])
.substThis(tps[j].symbol(), lubThisType);
rlbs[j] = tps[j].memberLoBound(rsyms[j])
.substThis(tps[j].symbol(), lubThisType);
if (rtps[j].isSameAs(symType) &&
rlbs[j].isSameAs(symLoBound)) break;
j++;
}
if (j == tps.length) {
Symbol lubSym = lub(rsyms, rtps, rlbs, lubType.symbol());
if (lubSym.kind != NONE &&
!(lubSym.kind == e.sym.kind &&
lubSym.info().isSameAs(symType) &&
lubSym.loBound().isSameAs(symType)))
members.enter(lubSym);
}
}
}
}
//System.out.print("lub "); System.out.print(ArrayApply.toString(tps)); System.out.println(" = " + lubType);//DEBUG
if (leastBaseTypes.length == 1 && members.elems == Scope.Entry.NONE)
return leastBaseTypes[0];
else return lubType;
}
//where
private static Type memberTp(Type base, Symbol sym) {
return sym.kind == CLASS ? base.memberType(sym) : base.memberInfo(sym);
}
private static Symbol lub(Symbol[] syms, Type[] tps, Type[] lbs, Symbol owner) {
//System.out.println("lub" + ArrayApply.toString(syms));//DEBUG
int lubKind = syms[0].kind;
for (int i = 1; i < syms.length; i++) {
Symbol sym = syms[i];
if (sym.kind == ERROR) return Symbol.NONE;
if (sym.isType() && sym.kind != lubKind) lubKind = TYPE;
}
if (lubKind == syms[0].kind && tps[0].isSameAsAll(tps)) {
return syms[0].cloneSymbol();
}
Type lubType = lub(tps);
if (lubType == Type.NoType) return Symbol.NONE;
Symbol lubSym;
switch (lubKind) {
case VAL:
lubSym = new TermSymbol(syms[0].pos, syms[0].name, owner, 0);
break;
case TYPE: case ALIAS: case CLASS:
lubSym = new AbsTypeSymbol(syms[0].pos, syms[0].name, owner, 0);
lubSym.setLoBound(glb(lbs));
break;
default:
throw new ApplicationError();
}
lubSym.setInfo(lubType);
return lubSym;
}
public static Type glb(Type[] tps) {
if (tps.length == 0) return Global.instance.definitions.ANY_TYPE;
// step one: eliminate redunandant types; return if one one is left
tps = elimRedundant(tps, false);
if (tps.length == 1) return tps[0];
// step two: build arrays of all typerefs and all refinements
Type.List treftl = Type.List.EMPTY;
Type.List comptl = Type.List.EMPTY;
for (int i = 0; i < tps.length; i++) {
switch (tps[i]) {
case TypeRef(_, _, _):
treftl = new Type.List(tps[i], treftl);
break;
case CompoundType(Type[] parents, Scope members):
if (members.elems != Scope.Entry.NONE)
comptl = new Type.List(tps[i], comptl);
for (int j = 0; j < parents.length; j++)
treftl = new Type.List(parents[i], treftl);
break;
case ThisType(_):
case SingleType(_, _):
return Global.instance.definitions.ALL_TYPE;
}
}
CompoundType glbType = compoundType(Type.EMPTY_ARRAY, new Scope());
Type glbThisType = glbType.narrow();
// step 3: compute glb of all refinements.
Scope members = Scope.EMPTY;
if (comptl != List.EMPTY) {
Type[] comptypes = comptl.toArrayReverse();
Scope[] refinements = new Scope[comptypes.length];
for (int i = 0; i < comptypes.length; i++)
refinements[i] = comptypes[i].members();
if (!setGlb(glbType.members, refinements, glbThisType)) {
// refinements don't have lower bound, so approximate
// by AllRef
glbType.members = Scope.EMPTY;
treftl = new Type.List(
Global.instance.definitions.ALLREF_TYPE, treftl);
}
}
// eliminate redudant typerefs
Type[] treftypes = elimRedundant(treftl.toArrayReverse(), false);
if (treftypes.length != 1 || glbType.members.elems != Scope.Entry.NONE) {
// step 4: replace all abstract types by their lower bounds.
boolean hasAbstract = false;
for (int i = 0; i < treftypes.length; i++) {
if (treftypes[i].unalias().symbol().kind == TYPE)
hasAbstract = true;
}
if (hasAbstract) {
treftl = Type.List.EMPTY;
for (int i = 0; i < treftypes.length; i++) {
if (treftypes[i].unalias().symbol().kind == TYPE)
treftl = new Type.List(treftypes[i].loBound(), treftl);
else
treftl = new Type.List(treftypes[i], treftl);
}
treftypes = elimRedundant(treftl.toArrayReverse(), false);
}
}
if (treftypes.length != 1) {
// step 5: if there are conflicting instantiations of same
// class, replace them by lub/glb of arguments or lower bound.
Type lb = NoType;
for (int i = 0;
i < treftypes.length &&
lb.symbol() != Global.instance.definitions.ALL_CLASS;
i++) {
for (int j = 0; j < i; j++) {
if (treftypes[j].symbol() == treftypes[i].symbol())
lb = argGlb(treftypes[j], treftypes[i]);
}
}
if (lb != NoType) return lb;
}
if (treftypes.length == 1 && glbType.members.elems == Scope.Entry.NONE) {
return treftypes[0];
} else {
glbType.parts = treftypes;
return glbType;
}
}
private static Type argGlb(Type tp1, Type tp2) {
switch (tp1) {
case TypeRef(Type pre1, Symbol sym1, Type[] args1):
switch (tp2) {
case TypeRef(Type pre2, Symbol sym2, Type[] args2):
assert sym1 == sym2;
if (pre1.isSameAs(pre2)) {
Symbol[] tparams = sym1.typeParams();
Type[] args = new Type[tparams.length];
for (int i = 0; i < tparams.length; i++) {
if (args1[i].isSameAs(args2[i]))
args[i] = args1[i];
else if ((tparams[i].flags & COVARIANT) != 0)
args[i]= lub(new Type[]{args1[i], args2[i]});
else if ((tparams[i].flags & CONTRAVARIANT) != 0)
args[i]= glb(new Type[]{args1[i], args2[i]});
else
return glb(new Type[]{tp1.loBound(), tp2.loBound()});
}
return typeRef(pre1, sym1, args);
}
}
}
return glb(new Type[]{tp1.loBound(), tp2.loBound()});
}
/** Set scope `result' to glb of scopes `ss'. Return true iff succeeded.
*/
private static boolean setGlb(Scope result, Scope[] ss, Type glbThisType) {
for (int i = 0; i < ss.length; i++)
for (Scope.Entry e = ss[i].elems; e != Scope.Entry.NONE; e = e.next)
if (!addMember(result, e.sym, glbThisType)) return false;
return true;
}
/** Add member `sym' to scope `s'. If`s' has already a member with same name,
* overwrite its info/low bound to form glb of both symbols.
*/
private static boolean addMember(Scope s, Symbol sym, Type glbThisType) {
Type syminfo = sym.info().substThis(sym.owner(), glbThisType);
Type symlb = sym.loBound().substThis(sym.owner(), glbThisType);
Scope.Entry e = s.lookupEntry(sym.name);
if (e == Scope.Entry.NONE) {
Symbol sym1 = sym.cloneSymbol(glbThisType.symbol());
sym1.setInfo(syminfo);
if (sym1.kind == TYPE) sym1.setLoBound(symlb);
s.enter(sym1);
} else {
Type einfo = e.sym.info();
if (einfo.isSameAs(syminfo)) {
} else if (einfo.isSubType(syminfo) && sym.kind != ALIAS) {
} else if (syminfo.isSubType(einfo) && e.sym.kind != ALIAS) {
e.sym.setInfo(syminfo);
} else if (sym.kind == VAL && e.sym.kind == VAL ||
sym.kind == TYPE && e.sym.kind == TYPE) {
e.sym.setInfo(glb(new Type[]{einfo, syminfo}));
} else {
return false;
}
if (e.sym.kind == TYPE && sym.kind == TYPE) {
Type elb = e.sym.loBound();
if (elb.isSameAs(symlb)) {
} else if (symlb.isSubType(elb)) {
} else if (elb.isSubType(symlb)) {
e.sym.setLoBound(symlb);
} else {
e.sym.setLoBound(lub(new Type[]{elb, symlb}));
}
}
}
return true;
}
// Erasure --------------------------------------------------------------------------
public static Map erasureMap = new MapOnlyTypes() {
public Type apply(Type t) { return t.erasure(); }
};
private static final Type[] unboxedType =
new Type[LastUnboxedTag + 1 - FirstUnboxedTag];
private static final Type[] unboxedArrayType =
new Type[LastUnboxedTag + 1 - FirstUnboxedTag];
private static final Name[] unboxedName =
new Name[LastUnboxedTag + 1 - FirstUnboxedTag];
private static final Name[] boxedName =
new Name[LastUnboxedTag + 1 - FirstUnboxedTag];
private static final Name[] boxedFullName =
new Name[LastUnboxedTag + 1 - FirstUnboxedTag];
private static void mkStdClassType(int kind, String unboxedstr, String boxedstr) {
unboxedType[kind - FirstUnboxedTag] = UnboxedType(kind);
unboxedArrayType[kind - FirstUnboxedTag] = UnboxedArrayType(unboxedType(kind));
unboxedName[kind - FirstUnboxedTag] = Name.fromString(unboxedstr);
boxedName[kind - FirstUnboxedTag] = Name.fromString(boxedstr);
boxedFullName[kind - FirstUnboxedTag] = Name.fromString("scala." + boxedstr);
}
static {
mkStdClassType(BYTE, "byte", "Byte");
mkStdClassType(SHORT, "short", "Short");
mkStdClassType(CHAR, "char", "Char");
mkStdClassType(INT, "int", "Int");
mkStdClassType(LONG, "long", "Long");
mkStdClassType(FLOAT, "float", "Float");
mkStdClassType(DOUBLE, "double", "Double");
mkStdClassType(BOOLEAN, "boolean", "Boolean");
mkStdClassType(UNIT, "void", "Unit");
}
/** Return unboxed type of given kind.
*/
public static Type unboxedType(int kind) {
return unboxedType[kind - FirstUnboxedTag];
}
/** Return unboxed array type of given element kind.
*/
public static Type unboxedArrayType(int kind) {
return unboxedArrayType[kind - FirstUnboxedTag];
}
/** Return the name of unboxed type of given kind.
*/
public static Name unboxedName(int kind) {
return unboxedName[kind - FirstUnboxedTag];
}
/** Return the name of boxed type of given kind.
*/
public static Name boxedName(int kind) {
return boxedName[kind - FirstUnboxedTag];
}
/** Return the full name of boxed type of given kind.
*/
public static Name boxedFullName(int kind) {
return boxedFullName[kind - FirstUnboxedTag];
}
/** If type is boxed, return its unboxed equivalent; otherwise return the type
* itself.
*/
public Type unbox() {
switch (this) {
case TypeRef(Type pre, Symbol sym, Type[] args):
if ((sym.flags & MODUL) == 0) {
Name fullname = sym.fullName();
if (fullname == Names.scala_Array && args.length == 1) {
Type bound = upperBound(args[0]);
// todo: check with Philippe if this is what we want.
if (bound.symbol() != Global.instance.definitions.ANY_CLASS &&
bound.symbol() != Global.instance.definitions.ANYVAL_CLASS)
{
return UnboxedArrayType(args[0].erasure());
}
}
for (int i = 0; i < boxedFullName.length; i++) {
if (boxedFullName[i] == fullname) return unboxedType[i];
}
}
}
return this;
}
//where
private Type upperBound(Type tp) {
switch (tp) {
case TypeRef(Type pre, Symbol sym, Type[] args):
if (sym.kind == ALIAS || sym.kind == TYPE)
return upperBound(pre.memberInfo(sym));
}
return tp;
}
/** Return the erasure of this type.
*/
public Type erasure() {
switch (this) {
case ThisType(_):
case SingleType(_, _):
return singleDeref().erasure();
case TypeRef(Type pre, Symbol sym, Type[] args):
switch (sym.kind) {
case ALIAS: case TYPE:
return pre.memberInfo(sym).erasure();
case CLASS:
if (sym == Global.instance.definitions.UNIT_CLASS) return this;
Name fullname = sym.fullName();
if (fullname == Names.java_lang_Object ||
fullname == Names.scala_AnyRef ||
fullname == Names.scala_AnyVal ||
fullname == Names.scala_All ||
fullname == Names.scala_AllRef)
return Global.instance.definitions.ANY_TYPE;
else {
Type this1 = unbox();
if (this1 != this) return this1;
else return sym.typeConstructor();
}
default: throw new ApplicationError();
}
case CompoundType(Type[] parents, _):
if (parents.length > 0) return parents[0].erasure();
else return this;
case MethodType(Symbol[] params, Type tp):
Symbol[] params1 = erasureMap.map(params);
Type tp1 = tp.fullErasure();
switch (tp1) {
case MethodType(Symbol[] params2, Type tp2):
Symbol[] newparams = new Symbol[params1.length + params2.length];
System.arraycopy(params1, 0, newparams, 0, params1.length);
System.arraycopy(params2, 0, newparams, params1.length, params2.length);
return MethodType(newparams, tp2);
default:
if (params1 == params && tp1 == tp) return this;
else return MethodType(params1, tp1);
}
case PolyType(_, Type result):
return result.erasure();
default:
return erasureMap.map(this);
}
}
/** Return the full erasure of the type. Full erasure is the same
* as "normal" erasure, except that the "Unit" type is erased to
* the "void" type.
*/
public Type fullErasure() {
if (Global.instance.definitions.UNIT_CLASS == symbol())
return unbox();
else
return erasure();
}
// Object Interface -----------------------------------------------------------------
public String toString() {
return new SymbolTablePrinter().printType(this).toString();
}
public String toLongString() {
String str = toString();
if (str.endsWith(".type")) return str + " (with underlying type " + widen() + ")";
else return str;
}
public int hashCode() {
switch (this) {
case ErrorType:
return ERROR;
case NoType:
return NOtpe;
case ThisType(Symbol sym):
return THIStpe
^ (sym.hashCode() * 41);
case TypeRef(Type pre, Symbol sym, Type[] args):
return NAMEDtpe
^ (pre.hashCode() * 41)
^ (sym.hashCode() * (41*41))
^ (hashCode(args) * (41*41*41));
case SingleType(Type pre, Symbol sym):
return SINGLEtpe
^ (pre.hashCode() * 41)
^ (sym.hashCode() * (41*41));
case CompoundType(Type[] parts, Scope members):
return COMPOUNDtpe
^ (hashCode(parts) * 41)
^ (members.hashCode() * (41 * 41));
case MethodType(Symbol[] vparams, Type result):
return METHODtpe
^ (hashCode(Symbol.type(vparams)) * 41)
^ (result.hashCode() * (41 * 41));
case PolyType(Symbol[] tparams, Type result):
return POLYtpe
^ (hashCode(tparams) * 41)
^ (result.hashCode() * (41 * 41));
case OverloadedType(Symbol[] alts, Type[] alttypes):
return OVERLOADEDtpe
^ (hashCode(alts) * 41)
^ (hashCode(alttypes) * (41 * 41));
case UnboxedType(int kind):
return UNBOXEDtpe
^ (kind * 41);
case UnboxedArrayType(Type elemtp):
return UNBOXEDARRAYtpe
^ (elemtp.hashCode() * 41);
default:
throw new ApplicationError();
}
}
public static int hashCode(Object[] elems) {
int h = 0;
for (int i = 0; i < elems.length; i++)
h = h * 41 + elems[i].hashCode();
return h;
}
public static int hashCode(Scope.Entry elems) {
int h = 0;
for (Scope.Entry e = elems; e != Scope.Entry.NONE; e = e.next)
h = h * 41
+ e.sym.kind
+ e.sym.name.hashCode()
+ e.sym.info().hashCode();
return h;
}
// todo: change in relation to needs.
public boolean equals(Object other) {
if (this == other) {
return true;
} else if (other instanceof Type) {
Type that = (Type) other;
switch (this) {
case ErrorType:
return that == ErrorType;
case NoType:
return that == NoType;
case ThisType(Symbol sym):
switch (that) {
case ThisType(Symbol sym1):
return sym == sym1;
default: return false;
}
case TypeRef(Type pre, Symbol sym, Type[] args):
switch (that) {
case TypeRef(Type pre1, Symbol sym1, Type[] args1):
return pre.equals(pre1) && sym == sym1 && equals(args, args1);
default: return false;
}
case SingleType(Type pre, Symbol sym):
switch (that) {
case SingleType(Type pre1, Symbol sym1):
return pre.equals(pre1) && sym == sym1;
default: return false;
}
case CompoundType(Type[] parts, Scope members):
switch (that) {
case CompoundType(Type[] parts1, Scope members1):
return parts.equals(parts1) && members.equals(members1);
default: return false;
}
case MethodType(Symbol[] vparams, Type result):
switch (that) {
case MethodType(Symbol[] vparams1, Type result1):
return equals(Symbol.type(vparams), Symbol.type(vparams1)) &&
result.equals(result1);
default: return false;
}
case PolyType(Symbol[] tparams, Type result):
switch (that) {
case PolyType(Symbol[] tparams1, Type result1):
return equals(tparams, tparams1) && result.equals(result1);
default: return false;
}
case OverloadedType(Symbol[] alts, Type[] alttypes):
switch (that) {
case OverloadedType(Symbol[] alts1, Type[] alttypes1):
return equals(alts, alts1) && equals(alttypes, alttypes1);
default: return false;
}
case UnboxedType(int kind):
switch (that) {
case UnboxedType(int kind1):
return kind == kind1;
default: return false;
}
case UnboxedArrayType(Type elemtp):
switch (that) {
case UnboxedArrayType(Type elemtp1):
return elemtp.equals(elemtp1);
default: return false;
}
default:
}
}
return false;
}
public static boolean equals(Object[] elems1, Object[] elems2) {
if (elems1.length != elems2.length) return false;
for (int i = 0; i < elems1.length; i++) {
if (!elems1[i].equals(elems2[i])) return false;
}
return true;
}
// Type.List class -----------------------------------------------------------------
/** A class for lists of types.
*/
public static class List {
public Type head;
public List tail;
public List(Type head, List tail) {
this.head = head; this.tail = tail;
}
public int length() {
return (this == EMPTY) ? 0 : 1 + tail.length();
}
public Type[] toArray() {
Type[] ts = new Type[length()];
copyToArray(ts, 0, 1);
return ts;
}
public void copyToArray(Type[] ts, int start, int delta) {
if (this != EMPTY) {
ts[start] = head;
tail.copyToArray(ts, start+delta, delta);
}
}
public Type[] toArrayReverse() {
Type[] ts = new Type[length()];
copyToArray(ts, ts.length - 1, -1);
return ts;
}
public String toString() {
if (this == EMPTY) return "List()";
else return head + "::" + tail;
}
public static List EMPTY = new List(null, null);
public static List append(List l, Type tp) {
return (l == EMPTY) ? new List(tp, EMPTY)
: new List(l.head, append(l.tail, tp));
}
}
// Type.Constraint class -------------------------------------------------------
/** A class for keeping sub/supertype constraints and instantiations
* of type variables.
*/
public static class Constraint {
public List lobounds = List.EMPTY;
public List hibounds = List.EMPTY;
public Type inst = NoType;
public boolean instantiate(Type tp) {
for (List l = lobounds; l != List.EMPTY; l = l.tail) {
if (!l.head.isSubType(tp)) return false;
}
for (List l = hibounds; l != List.EMPTY; l = l.tail) {
if (!tp.isSubType(l.head)) return false;
}
inst = tp;
return true;
}
}
// Type.Error class --------------------------------------------------------------
/** A class for throwing type errors
*/
public static class Error extends java.lang.Error {
public String msg;
public Error(String msg) {
super(msg);
this.msg = msg;
}
}
/** A class for throwing type errors
*/
public static class VarianceError extends Error {
public VarianceError(String msg) {
super(msg);
}
}
public static void explainTypes(Type found, Type required) {
if (Global.instance.explaintypes) {
boolean s = explainSwitch;
explainSwitch = true;
found.isSubType(required);
explainSwitch = s;
}
}
}
/* A standard pattern match:
case ErrorType:
case AnyType:
case NoType:
case ThisType(Symbol sym):
case TypeRef(Type pre, Symbol sym, Type[] args):
case SingleType(Type pre, Symbol sym):
case CompoundType(Type[] parts, Scope members):
case MethodType(Symbol[] vparams, Type result):
case PolyType(Symbol[] tparams, Type result):
case OverloadedType(Symbol[] alts, Type[] alttypes):
*/