/******************************************************************************
* Copyright (c) 2002 - 2006 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
*
* Contributors:
* IBM Corporation - initial API and implementation
*****************************************************************************/
package com.ibm.wala.cast.tree;
/**
* This interface represents nodes of CAPA Abstract Syntax Trees. It
* is a deliberately minimal interface, simply assuming that the nodes
* form a tree and have some minimal state at each node. In
* particular, a node has a kind---which should be one of the symbolic
* constants in this file---and potentially has child nodes, a
* constant values, or possibly both.
*
* Note that there is no support for mutating these trees. This is
* deliberate, and should not be changed. We do not want to force all
* clients of the capa ast to handle mutating programs. In
* particular, the DOMO infrastructure has many forms of caching and
* other operations that rely on the underlying program being
* immutable. If you need to mutate these trees for some reason---and
* think carefully if you really need to, since this is meant to be
* essentially a wire format between components---make specialized
* implementations that understand how to do that.
*
* Also note that this interface does not assume that you need some
* great big class hierarchy to structure types of nodes in an ast.
* Some people prefer such hierarchies as a matter of taste, but this
* interface is designed to not inflict this design choice on others.
*
* Finally note that the set of node types in this file is not meant
* to be exhaustive. As new languages are added, feel free to add new
* nodes types as needed.
*
* @author Julian Dolby (dolby@us.ibm.com)
* @author Robert M. Fuhrer (rfuhrer@watson.ibm.com)
*
*/
public interface CAstNode {
// statement kinds
/**
* Represents a standard case statement. Children:
* </ul>
* <li>condition expression
* <li>BLOCK_STMT containing all the cases
* </ul>
*/
public static final int SWITCH = 1;
/**
* Represents a standard while loop. Children:
* <ul>
* <li>expression denoting the loop condition
* <li>statement denoting the loop body
* </ul>
*/
public static final int LOOP = 2;
/**
* Represents a block of sequential statements. Children:
* <ul>
* <li>statement #1
* <li>statement #2
* <li>...
* </ul>
*/
public static final int BLOCK_STMT = 3;
/**
* Represents a standard try/catch statement. Note that while some
* languages choose to bundle together the notion of try/catch and
* the notion of unwind-protect (aka 'finally'), the CAst does not.
* There is a separate UNWIND node type. Children:
* <ul>
* <li>the code of the try block.
* <li>the code of the catch block <li>...
* </ul>
*/
public static final int TRY = 4;
/**
* Represents an expression statement (e.g. "foo();"). Children:
* <ul>
* <li>the expression
* </ul>
*/
public static final int EXPR_STMT = 5;
public static final int DECL_STMT = 6;
public static final int RETURN = 7;
public static final int GOTO = 8;
public static final int BREAK = 9;
public static final int CONTINUE = 10;
public static final int IF_STMT = 11;
public static final int THROW = 12;
public static final int FUNCTION_STMT = 13;
public static final int ASSIGN = 14;
public static final int ASSIGN_PRE_OP = 15;
public static final int ASSIGN_POST_OP = 16;
public static final int LABEL_STMT = 17;
public static final int IFGOTO = 18;
public static final int EMPTY = 19;
public static final int RETURN_WITHOUT_BRANCH = 20;
public static final int CATCH = 21;
public static final int UNWIND = 22;
public static final int MONITOR_ENTER = 23;
public static final int MONITOR_EXIT = 24;
public static final int ECHO = 25;
public static final int YIELD_STMT = 26;
public static final int FORIN_LOOP = 27;
// expression kinds
public static final int FUNCTION_EXPR = 100;
public static final int EXPR_LIST = 101;
public static final int CALL = 102;
public static final int GET_CAUGHT_EXCEPTION = 103;
/**
* Represents a block of sequentially-executed nodes, the last of which produces
* the value for the entire block (like progn from lisp).
* Children:
* <ul>
* <li>node 1
* <li>node 2
* <li>...
* <li>block value expression
* </ul>
*/
public static final int BLOCK_EXPR = 104;
public static final int BINARY_EXPR = 105;
public static final int UNARY_EXPR = 106;
public static final int IF_EXPR = 107;
public static final int ANDOR_EXPR = 108; // TODO blow away?
public static final int NEW = 109;
public static final int OBJECT_LITERAL = 110;
public static final int VAR = 111;
public static final int OBJECT_REF = 112;
public static final int CHOICE_EXPR = 113;
public static final int CHOICE_CASE = 114;
public static final int SUPER = 115;
public static final int THIS = 116;
public static final int ARRAY_LITERAL = 117;
public static final int CAST = 118;
public static final int INSTANCEOF = 119;
public static final int ARRAY_REF = 120;
public static final int ARRAY_LENGTH = 121;
public static final int TYPE_OF = 122;
public static final int EACH_ELEMENT_HAS_NEXT = 123;
public static final int EACH_ELEMENT_GET = 124;
public static final int LIST_EXPR = 125;
public static final int EMPTY_LIST_EXPR = 126;
public static final int TYPE_LITERAL_EXPR = 127;
public static final int IS_DEFINED_EXPR = 128;
public static final int MACRO_VAR = 129;
// new nodes with an explicit enclosing argument, e.g. "outer.new Inner()". They are mostly treated the same, except in JavaCAst2IRTranslator.doNewObject
public static final int NEW_ENCLOSING = 130;
// explicit lexical scopes
public static final int LOCAL_SCOPE = 200;
public static final int SPECIAL_PARENT_SCOPE = 201;
// literal expression kinds
public static final int CONSTANT = 300;
public static final int OPERATOR = 301;
// special stuff
public static final int PRIMITIVE = 400;
public static final int ERROR = 401;
public static final int VOID = 402;
public static final int ASSERT = 403;
public static final int INCLUDE = 404;
public static final int NAMED_ENTITY_REF = 405;
public static final int SUB_LANGUAGE_BASE = 1000;
/**
* What kind of node is this? Should return some constant from this file.
*/
int getKind();
/**
* Returns the constant value represented by this node, if
* appropriate, and null otherwise.
*/
Object getValue();
/**
* Return the nth child of this node. If there is no such child,
* this method should throw a NoSuchElementException.
*/
CAstNode getChild(int n);
/**
* How many children does this node have?
*/
int getChildCount();
}