/interpreter/tags/at2dist041108/src/edu/vub/at/objects/natives/grammar/AGDefField.java
Java | 114 lines | 47 code | 14 blank | 53 comment | 0 complexity | 324cdc884bc4a9ce6d9143962b42cc90 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.ATDefinition; 35import edu.vub.at.objects.grammar.ATExpression; 36import edu.vub.at.objects.grammar.ATSymbol; 37import edu.vub.at.objects.natives.NATText; 38 39import java.util.HashSet; 40import java.util.Set; 41 42/** 43 * @author tvc 44 * 45 * AGDefField represents the abstract grammar for defining fields. 46 * Examples: 47 * <tt>x := 5</tt> 48 * <tt>+ := "foo"</tt> 49 */ 50public final class AGDefField extends AGDefinition implements ATDefField { 51 52 private final ATSymbol name_; 53 private final ATExpression valueExp_; 54 55 public AGDefField(ATSymbol name, ATExpression value) { 56 name_ = name; 57 valueExp_ = value; 58 } 59 60 public ATSymbol base_name() { return name_; } 61 public ATExpression base_valueExpression() { return valueExp_; } 62 63 /** 64 * Defines a new field in the current scope. The return value is 65 * the evaluated value. 66 * 67 * AGDEFFIELD(nam,val).eval(ctx) = 68 * ctx.scope.addField(nam, val.eval(ctx)) 69 */ 70 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 71 ATObject val = valueExp_.meta_eval(ctx); 72 ctx.base_lexicalScope().meta_defineField(name_, val); 73 return val; 74 } 75 76 /** 77 * Quoting a field definition results in a new quoted field definition. 78 * 79 * AGDEFFIELD(nam,val).quote(ctx) = AGDEFFIELD(nam.quote(ctx), val.quote(ctx)) 80 */ 81 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 82 return new AGDefField(name_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression()); 83 } 84 85 public NATText meta_print() throws InterpreterException { 86 return NATText.atValue("def " + name_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue); 87 } 88 89 /** 90 * IV(def x := val) = { x } 91 */ 92 public Set impl_introducedVariables() throws InterpreterException { 93 HashSet singleton = new HashSet(); 94 singleton.add(name_); 95 return singleton; 96 } 97 98 /** 99 * FV(def var := exp) = FV(exp) \ { var } 100 */ 101 public Set impl_freeVariables() throws InterpreterException { 102 Set fvValueExp = valueExp_.impl_freeVariables(); 103 fvValueExp.remove(name_); 104 return fvValueExp; 105 } 106 107 108 public Set impl_quotedFreeVariables() throws InterpreterException { 109 Set qfv = valueExp_.impl_quotedFreeVariables(); 110 qfv.addAll(name_.impl_quotedFreeVariables()); 111 return qfv; 112 } 113 114}