/interpreter/tags/at2-build270707/src/edu/vub/at/objects/natives/grammar/AGDefField.java
Java | 85 lines | 29 code | 9 blank | 47 comment | 0 complexity | db04db0b5d20fb76098e89fc4f02fedb MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGDefField.java created on 26-jul-2006 at 12:14:43 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.objects.ATContext; 32import edu.vub.at.objects.ATObject; 33import edu.vub.at.objects.grammar.ATDefField; 34import edu.vub.at.objects.grammar.ATExpression; 35import edu.vub.at.objects.grammar.ATSymbol; 36import edu.vub.at.objects.natives.NATText; 37 38/** 39 * @author tvc 40 * 41 * AGDefField represents the abstract grammar for defining fields. 42 * Examples: 43 * <tt>x := 5</tt> 44 * <tt>+ := "foo"</tt> 45 */ 46public final class AGDefField extends NATAbstractGrammar implements ATDefField { 47 48 private final ATSymbol name_; 49 private final ATExpression valueExp_; 50 51 public AGDefField(ATSymbol name, ATExpression value) { 52 name_ = name; 53 valueExp_ = value; 54 } 55 56 public ATSymbol base_name() { return name_; } 57 public ATExpression base_valueExpression() { return valueExp_; } 58 59 /** 60 * Defines a new field in the current scope. The return value is 61 * the evaluated value. 62 * 63 * AGDEFFIELD(nam,val).eval(ctx) = 64 * ctx.scope.addField(nam, val.eval(ctx)) 65 */ 66 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 67 ATObject val = valueExp_.meta_eval(ctx); 68 ctx.base_lexicalScope().meta_defineField(name_, val); 69 return val; 70 } 71 72 /** 73 * Quoting a field definition results in a new quoted field definition. 74 * 75 * AGDEFFIELD(nam,val).quote(ctx) = AGDEFFIELD(nam.quote(ctx), val.quote(ctx)) 76 */ 77 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 78 return new AGDefField(name_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression()); 79 } 80 81 public NATText meta_print() throws InterpreterException { 82 return NATText.atValue("def " + name_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue); 83 } 84 85}