/*******************************************************************************
 * This file is part of the Polyglot extensible compiler framework.
 *
 * Copyright (c) 2000-2012 Polyglot project group, Cornell University
 * Copyright (c) 2006-2012 IBM Corporation
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * This program and the accompanying materials are made available under
 * the terms of the Lesser GNU Public License v2.0 which accompanies this
 * distribution.
 * 
 * The development of the Polyglot project has been supported by a
 * number of funding sources, including DARPA Contract F30602-99-1-0533,
 * monitored by USAF Rome Laboratory, ONR Grants N00014-01-1-0968 and
 * N00014-09-1-0652, NSF Grants CNS-0208642, CNS-0430161, CCF-0133302,
 * and CCF-1054172, AFRL Contract FA8650-10-C-7022, an Alfred P. Sloan 
 * Research Fellowship, and an Intel Research Ph.D. Fellowship.
 *
 * See README for contributors.
 ******************************************************************************/

package polyglot.ast;

import java.util.List;

import polyglot.translate.ExtensionRewriter;
import polyglot.types.SemanticException;
import polyglot.util.InternalCompilerError;
import polyglot.util.Position;
import polyglot.util.SerialVersionUID;
import polyglot.visit.CFGBuilder;

/**
 * An immutable representation of a loop
 * statement.  Contains a statement to be executed and an expression
 * to be tested indicating whether to reexecute the statement.
 */
public interface Loop extends CompoundStmt {
    /** Loop condition. */
    Expr cond();

    /** Set the loop condition. */
    Loop cond(Expr cond);

    /** Loop body. */
    Stmt body();

    /** Set the loop body. */
    Loop body(Stmt body);

    class Instance extends Loop_c {
        private static final long serialVersionUID =
                SerialVersionUID.generate();

        public Instance(Position pos, Expr cond, Stmt body, Ext ext) {
            super(pos, cond, body, ext);
            assert (ext != null);
        }

        @Override
        public final Node extRewrite(ExtensionRewriter rw)
                throws SemanticException {
            throw new InternalCompilerError("This loop cannot be represented in the "
                    + "target language and should have been rewritten: " + this);
        }

        @Override
        public final Term firstChild() {
            throw new InternalCompilerError("Unexpected invocation from extension object: "
                    + this);
        }

        @Override
        public final <T> List<T> acceptCFG(CFGBuilder<?> v, List<T> succs) {
            throw new InternalCompilerError("Unexpected invocation from extension object: "
                    + this);
        }

        @Override
        public final Term continueTarget() {
            throw new InternalCompilerError("Unexpected invocation from extension object: "
                    + this);
        }
    }
}
