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|
/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
** **
** $Id$
\* */
package scalac.transformer.matching;
import scala.tools.util.Position;
import scalac.*;
import scalac.ast.*;
import scalac.atree.AConstant;
import scalac.symtab.*;
import scalac.typechecker.*;
/** Intermediate data structure for algebraic + pattern matcher
*/
public class PatternNode {
public int pos = Position.FIRSTPOS;
public Type type;
public PatternNode or;
public PatternNode and;
public case Header(Tree selector, Header next) ;
public case Body(Tree.ValDef[][] bound, Tree[] guard, Tree[] body);
public case DefaultPat();
public case ConstrPat(Symbol casted);
public case ConstantPat(AConstant value);
public case VariablePat(Tree tree);
public case AltPat(Header subheader);
public case SequencePat(Symbol casted, int len); // only used in PatternMatcher
public case SeqContainerPat(Symbol casted, Tree seqpat); // in AlgebraicMatcher
public PatternNode dup() {
PatternNode res;
switch (this) {
case Header(Tree selector, Header next):
res = Header(selector, next);
break;
case Body(Tree.ValDef[][] bound, Tree[] guard, Tree[] body):
res = Body(bound, guard, body);
break;
case DefaultPat():
res = DefaultPat();
break;
case ConstrPat(Symbol casted):
res = ConstrPat(casted);
break;
case SequencePat(Symbol casted, int len):
res = SequencePat(casted, len);
break;
case SeqContainerPat(Symbol casted, Tree seqpat):
res = SeqContainerPat(casted, seqpat);
break;
case ConstantPat(AConstant value):
res = ConstantPat(value);
break;
case VariablePat(Tree tree):
res = VariablePat(tree);
break;
case AltPat(Header subheader):
res = AltPat(subheader);
break;
default:
throw new ApplicationError();
}
res.pos = pos;
res.type = type;
res.or = or;
res.and = and;
return res;
}
public Symbol symbol() {
switch (this) {
case ConstrPat(Symbol casted):
return casted;
case SequencePat(Symbol casted, _):
return casted;
case SeqContainerPat(Symbol casted, _):
return casted;
default:
return Symbol.NONE;
}
}
public PatternNode next() {
switch (this) {
case Header(_, Header next):
return next;
default:
return null;
}
}
public final boolean isDefaultPat() {
switch( this ) {
case DefaultPat():
return true;
default:
return false;
}
}
/** returns true if
* p and q are equal (constructor | sequence) type tests, or
* "q matches" => "p matches"
*/
public final boolean isSameAs( PatternNode q ) {
switch( this ) {
case ConstrPat(_):
switch (q) {
case ConstrPat(_):
return q.type.isSameAs( this.type );
}
return false;
case SequencePat(_, int plen):
switch (q) {
case SequencePat(_, int qlen):
return (plen == qlen) && q.type.isSameAs( this.type );
}
return false;
default:
return subsumes( q );
}
}
/** returns true if "q matches" => "p matches"
*/
public final boolean subsumes( PatternNode q ) {
switch (this) {
case DefaultPat():
switch (q) {
case DefaultPat():
return true;
}
return false;
case ConstrPat(_):
switch (q) {
case ConstrPat(_):
return q.type.isSubType(this.type);
}
return false;
case SequencePat(_, int plen):
switch (q) {
case SequencePat(_, int qlen):
return (plen == qlen) && q.type.isSubType(this.type);
}
return false;
case ConstantPat(AConstant pval):
switch (q) {
case ConstantPat(AConstant qval):
return pval.equals(qval);
}
return false;
case VariablePat(Tree tree):
switch (q) {
case VariablePat(Tree other):
return (tree.symbol() != null) &&
(tree.symbol().kind != Kinds.NONE) &&
(tree.symbol().kind != Kinds.ERROR) &&
(tree.symbol() == other.symbol());
}
return false;
}
return false;
}
public String toString() {
switch (this) {
case Header(Tree selector, Header next):
return "Header(" + selector + ")";
case Body( _, _, _ ):
return "Body";
case DefaultPat():
return "DefaultPat";
case ConstrPat(Symbol casted):
return "ConstrPat(" + casted + ")";
case SequencePat(Symbol casted, int len):
return "SequencePat(" + casted + ", " + len + "...)";
case SeqContainerPat(Symbol casted, Tree seqpat):
return "SeqContainerPat(" + casted + ", " + seqpat + ")";
case ConstantPat(AConstant value):
return "ConstantPat(" + value + ")";
case VariablePat(Tree tree):
return "VariablePat";
default:
return "<unknown pat>";
}
}
}
|
