/interpreter/tags/at2dist130208/src/edu/vub/at/objects/natives/grammar/AGUnquoteSplice.java
Java | 88 lines | 31 code | 11 blank | 46 comment | 0 complexity | 1311e4de12be94f83d32bf9cc7ff4467 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGUnquoteSplice.java created on 26-jul-2006 at 16:31:07 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.XIllegalQuote; 32import edu.vub.at.exceptions.XIllegalUnquote; 33import edu.vub.at.objects.ATContext; 34import edu.vub.at.objects.ATObject; 35import edu.vub.at.objects.grammar.ATExpression; 36import edu.vub.at.objects.grammar.ATUnquoteSplice; 37import edu.vub.at.objects.natives.NATText; 38 39/** 40 * @author tvc 41 * 42 * The native implementation of an unquote-splice AG element. 43 */ 44public class AGUnquoteSplice extends AGExpression implements ATUnquoteSplice { 45 46 private final ATExpression uqsExp_; 47 48 public AGUnquoteSplice(ATExpression exp) { 49 uqsExp_ = exp; 50 } 51 52 public ATExpression base_expression() { return uqsExp_; } 53 54 /** 55 * An unquotation cannot be evaluated, but rather gives rise to an XIllegalUnquote exception. 56 * This is because an unquotation should always be nested within a quotation. 57 * 58 * AGUQS(exp).eval(ctx) = ERROR 59 */ 60 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 61 throw new XIllegalUnquote(uqsExp_); 62 } 63 64 /** 65 * Quoting a spliced unquotation means evaluating its contained expression, and returning 66 * its value as the result of the quote. A spliced unquotation can normally only 67 * be invoked where a table or begin is expected. The resulting table is replaced by the result of 68 * evaluating the unquote-splice's encapsulated expression. 69 * 70 * It is the table's responsibility to query an AGUnquoteSplice element for its expression and deal with the inlining appropriately. 71 */ 72 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 73 throw new XIllegalQuote(uqsExp_.meta_print().javaValue); 74 } 75 76 public NATText meta_print() throws InterpreterException { 77 return NATText.atValue("#@("+ uqsExp_.meta_print().javaValue + ")"); 78 } 79 80 public boolean isUnquoteSplice() { 81 return true; 82 } 83 84 public ATUnquoteSplice asUnquoteSplice() { 85 return this; 86 } 87 88}