Special_c.java

/*
 *  This file is part of the X10 project (http://x10-lang.org).
 *
 *  This file is licensed to You under the Eclipse Public License (EPL);
 *  You may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *      http://www.opensource.org/licenses/eclipse-1.0.php
 *
 * This file was originally derived from the Polyglot extensible compiler framework.
 *
 *  (C) Copyright 2000-2007 Polyglot project group, Cornell University
 *  (C) Copyright IBM Corporation 2007-2012.
 */

package polyglot.ast;

import java.util.List;

import polyglot.types.*;
import polyglot.util.CodeWriter;
import polyglot.util.Position;
import polyglot.visit.*;

/**
 * A <code>Special</code> is an immutable representation of a
 * reference to <code>this</code> or <code>super</code in Java.  This
 * reference can be optionally qualified with a type such as 
 * <code>Foo.this</code>.
 */
public abstract class Special_c extends Expr_c implements Special
{
    protected Special.Kind kind;
    protected TypeNode qualifier;

    public Special_c(Position pos, Special.Kind kind, TypeNode qualifier) {
	super(pos);
	assert(kind != null); // qualifier may be null
	this.kind = kind;
	this.qualifier = qualifier;
    }

    /** Get the precedence of the expression. */
    public Precedence precedence() {
	return Precedence.LITERAL;
    }

    /** Get the kind of the special expression, either this or super. */
    public Special.Kind kind() {
	return this.kind;
    }

    /** Set the kind of the special expression, either this or super. */
    public Special kind(Special.Kind kind) {
	Special_c n = (Special_c) copy();
	n.kind = kind;
	return n;
    }

    /** Get the qualifier of the special expression. */
    public TypeNode qualifier() {
	return this.qualifier;
    }

    /** Set the qualifier of the special expression. */
    public Special qualifier(TypeNode qualifier) {
	Special_c n = (Special_c) copy();
	n.qualifier = qualifier;
	return n;
    }

    /** Reconstruct the expression. */
    protected Special_c reconstruct(TypeNode qualifier) {
	if (qualifier != this.qualifier) {
	    Special_c n = (Special_c) copy();
	    n.qualifier = qualifier;
	    return n;
	}

	return this;
    }

    /** Visit the children of the expression. */
    public Node visitChildren(NodeVisitor v) {
	TypeNode qualifier = (TypeNode) visitChild(this.qualifier, v);
	return reconstruct(qualifier);
    }

    /** Type check the expression. */
    public abstract Node typeCheck(ContextVisitor tc);

    public Term firstChild() {
        if (qualifier != null) {
            return qualifier;
        }
        
        return null;
    }

    public <S> List<S> acceptCFG(CFGBuilder v, List<S> succs) {
        if (qualifier != null) {
            v.visitCFG(qualifier, this, EXIT);
        }
        
        return succs;
    }

    public String toString() {
	return (qualifier != null ? qualifier + "." : "") + kind;
    }

    /** Write the expression to an output file. */
    public void prettyPrint(CodeWriter w, PrettyPrinter tr) {
	if (qualifier != null) {
	    print(qualifier, w, tr);
	    w.write(".");
	}

	w.write(kind.toString());
    }

    public void dump(CodeWriter w) {
      super.dump(w);

      if (kind != null) {
        w.allowBreak(4, " ");
        w.begin(0);
        w.write("(kind " + kind + ")");
        w.end();
      }
    }
    
}