1 /* 2 * Binding.java 3 * 4 * Copyright (C) 2002-2005 Peter Graves 5 * $Id$ 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 2 10 * of the License, or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 20 * 21 * As a special exception, the copyright holders of this library give you 22 * permission to link this library with independent modules to produce an 23 * executable, regardless of the license terms of these independent 24 * modules, and to copy and distribute the resulting executable under 25 * terms of your choice, provided that you also meet, for each linked 26 * independent module, the terms and conditions of the license of that 27 * module. An independent module is a module which is not derived from 28 * or based on this library. If you modify this library, you may extend 29 * this exception to your version of the library, but you are not 30 * obligated to do so. If you do not wish to do so, delete this 31 * exception statement from your version. 32 */ 33 34 package org.armedbear.lisp; 35 36 import java.io.Serializable; 37 38 /** Used by the environment to capture different kinds of bindings: 39 * tags, blocks, functions and variables. 40 * 41 */ 42 // Package accessibility. 43 final class Binding implements Serializable 44 { 45 /** The symbol in case of a variable, block, symbol-macro or 46 * non-SETF function binding, the tag (symbol or 47 * integer) in case of a tag binding or the cons 48 * in case of a SETF function binding 49 */ 50 final LispObject symbol; 51 52 /** Used only for tags and blocks. Refers to the 53 * defining environment. 54 * 55 */ 56 Environment env = null; 57 58 /** The value bound. 59 * 60 * In case of a block binding, it holds the block identifier to be used 61 * with the Return to be thrown. 62 * 63 * In case of a tagbody, it holds the tail subforms of the tagbody, of 64 * which the tag is the first subform. 65 * 66 * In case of a function binding, it holds the function object. 67 * 68 * In case of a variable binding, it holds the value associated with the 69 * variable, unless specialp is true. 70 * 71 * In case of a symbol macro binding, holds the SymbolMacro instance 72 * holding the macro's expansion. 73 */ 74 LispObject value; 75 76 /** Only used for variable bindings. Indicates whether or not the value 77 * should be retrieved from the dynamic environment or from this binding. 78 */ 79 boolean specialp; 80 final Binding next; 81 Binding(LispObject symbol, LispObject value, Binding next)82 Binding(LispObject symbol, LispObject value, Binding next) 83 { 84 this.symbol = symbol; 85 this.value = value; 86 this.next = next; 87 } 88 Binding(LispObject symbol, Environment env, LispObject value, Binding next)89 Binding(LispObject symbol, Environment env, 90 LispObject value, Binding next) 91 { 92 this(symbol, value, next); 93 this.env = env; 94 } 95 } 96