/interpreter/tags/at2dist220411/src/edu/vub/at/objects/natives/grammar/AGUnquote.java
Java | 99 lines | 36 code | 13 blank | 50 comment | 0 complexity | 8914be234e1dcd1f92bce45ec466fe57 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGUnquote.java created on 26-jul-2006 at 16:29:32 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.XIllegalUnquote; 32import edu.vub.at.objects.ATContext; 33import edu.vub.at.objects.ATObject; 34import edu.vub.at.objects.grammar.ATExpression; 35import edu.vub.at.objects.grammar.ATUnquote; 36import edu.vub.at.objects.natives.NATText; 37import edu.vub.util.TempFieldGenerator; 38 39import java.util.HashSet; 40import java.util.Set; 41 42/** 43 * The native implementation of an unquotation AG element. 44 * Example: <tt>#(x+1)</tt> 45 * 46 * @author tvcutsem 47 */ 48public class AGUnquote extends AGExpression implements ATUnquote { 49 50 protected final ATExpression unqExp_; 51 52 public AGUnquote(ATExpression exp) { 53 unqExp_ = exp; 54 } 55 56 public ATExpression base_expression() { return unqExp_; } 57 58 /** 59 * An unquotation cannot be evaluated, but rather gives rise to an XIllegalUnquote exception. 60 * This is because an unquotation should always be nested within a quotation. 61 * 62 * AGUNQ(exp).eval(ctx) = ERROR 63 */ 64 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 65 throw new XIllegalUnquote(unqExp_); 66 } 67 68 /** 69 * Quoting an unquotation means evaluating its contained expression, and returning 70 * its value as the result of the quote. 71 */ 72 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 73 return unqExp_.meta_eval(ctx); 74 } 75 76 public NATText meta_print() throws InterpreterException { 77 return NATText.atValue("#("+ unqExp_.meta_print().javaValue + ")"); 78 } 79 80 public NATText impl_asUnquotedCode(TempFieldGenerator objectMap) throws InterpreterException { 81 return NATText.atValue("#("+ unqExp_.impl_asUnquotedCode(objectMap).javaValue + ")"); 82 } 83 84 /** 85 * FV(#exp) = FV(exp) 86 */ 87 public Set impl_freeVariables() throws InterpreterException { 88 return unqExp_.impl_freeVariables(); 89 } 90 91 /** 92 * Turn unquotation back into quotation. 93 * E.g. `(x + #(y)) => y is considered a free variable 94 */ 95 public Set impl_quotedFreeVariables() throws InterpreterException { 96 return this.impl_freeVariables(); 97 } 98 99}