/interpreter/tags/at2dist030708/src/edu/vub/at/objects/natives/grammar/AGAssignmentSymbol.java
Java | 106 lines | 48 code | 13 blank | 45 comment | 2 complexity | 357ba8280bf79ea70f518805c25d8aa9 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGAssignmentSymbol.java created on 2-jul-2007 at 13:45:32 4 * (c) Programming Technology Lab, 2006 - 2007 5 * Authors: Tom Van Cutsem & Stijn Mostinckx 6 * 7 * Permission is hereby granted, free of charge, to any person 8 * obtaining a copy of this software and associated documentation 9 * files (the "Software"), to deal in the Software without 10 * restriction, including without limitation the rights to use, 11 * copy, modify, merge, publish, distribute, sublicense, and/or 12 * sell copies of the Software, and to permit persons to whom the 13 * Software is furnished to do so, subject to the following 14 * conditions: 15 * 16 * The above copyright notice and this permission notice shall be 17 * included in all copies or substantial portions of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 26 * OTHER DEALINGS IN THE SOFTWARE. 27 */ 28package edu.vub.at.objects.natives.grammar; 29 30import edu.vub.at.exceptions.InterpreterException; 31import edu.vub.at.exceptions.XIllegalOperation; 32import edu.vub.at.objects.ATContext; 33import edu.vub.at.objects.ATObject; 34import edu.vub.at.objects.ATText; 35import edu.vub.at.objects.grammar.ATAssignmentSymbol; 36import edu.vub.at.objects.grammar.ATSymbol; 37import edu.vub.at.objects.natives.NATText; 38 39/** 40 * An assignment symbol is created by suffixing an ordinary symbol with a :=. It can be created 41 * explicitly through qutoting and is created when assigning a field at base-level to map such 42 * assignments onto a method invocation. Also it can be created when explicitly defining accessor 43 * methods. 44 * 45 * @author smostinc 46 */ 47public class AGAssignmentSymbol extends AGSymbol implements ATAssignmentSymbol { 48 49 /** 50 * @param name a string with a ':=' suffix 51 */ 52 public static AGSymbol jAlloc(String name) { 53 synchronized (_STRINGPOOL_) { 54 AGSymbol existing = (AGSymbol) _STRINGPOOL_.get(name); 55 if (existing == null) { 56 existing = new AGAssignmentSymbol(name); 57 _STRINGPOOL_.put(name, existing); 58 } 59 return existing; 60 } 61 } 62 63 protected AGAssignmentSymbol(String txt) { 64 // cut the := part of the symbol name, e.g. foo:= -> foo 65 super(txt.substring(0,txt.length()-2)); 66 } 67 68 public boolean isAssignmentSymbol() { 69 return true; 70 } 71 72 public AGAssignmentSymbol asAssignmentSymbol() { 73 return this; 74 } 75 76 public ATText base_text() { 77 return NATText.atValue(toString()); 78 } 79 80 /** 81 * It is illegal to evaluate an assignment symbol in base-level code 82 */ 83 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 84 throw new XIllegalOperation("Cannot evaluate an assignment symbol as an ordinary symbol"); 85 } 86 87 public NATText meta_print() { 88 return NATText.atValue(toString()); 89 } 90 91 public ATObject meta_resolve() throws InterpreterException { 92 return AGAssignmentSymbol.jAlloc(toString()); 93 } 94 95 public String toString() { 96 return super.toString() + ":="; 97 } 98 99 /** 100 * @return the field name being assigned by this assignment symbol 101 */ 102 public ATSymbol base_fieldName() { 103 return AGSymbol.jAlloc(super.toString()); 104 } 105 106}