/*
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.truffle.api.nodes.instrument;

/**
 * Categories of {@link InstrumentationProxyNode}s to be used for defining user-visible debugging
 * and other simple tool behavior. These categories (<em>phyla</em>) should correspond to program
 * structures that are meaningful to a programmer using the guest language. A Truffle node without a
 * proxy carrying some phylum should be treated as an artifact of the guest language implementation
 * and should never be visible to the user of a guest language programming tool.
 * <p>
 * Note that phyla are not intended to represent a partition of user-visible node categories, as the
 * relative categorization of nodes can change with the particular programming tasks at hand.
 * <p>
 * This is a somewhat language-agnostic set of phyla, suitable for conventional imperative
 * languages, and is being developed incrementally.
 * <p>
 * The need for alternative sets of phyla is likely to arise, perhaps for other families of
 * languages (for example for mostly expression-oriented languages) or even for specific languages.
 * <p>
 * These are listed alphabetically so that listing from some collection classes will come out in
 * that order.
 * <p>
 * <strong>Disclaimer:</strong> this interface is under development and will change.
 */
public enum NodePhylum {

    /**
     * Marker for a proxy at a variable assignment.
     */
    ASSIGNMENT,

    /**
     * Marker for a proxy at a call site.
     */
    CALL,

    /**
     * Marker for a proxy at which ordinary "stepping" should halt.
     */
    STATEMENT;

}