/interpreter/tags/at2dist090708/src/edu/vub/at/objects/natives/grammar/AGAssignVariable.java
Java | 99 lines | 45 code | 11 blank | 43 comment | 0 complexity | 13463c6906eb5c6fad390038f2e95c25 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGAssignVariable.java created on 26-jul-2006 at 15:54:48 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.eval.InvocationStack; 31import edu.vub.at.exceptions.InterpreterException; 32import edu.vub.at.exceptions.XTypeMismatch; 33import edu.vub.at.objects.ATContext; 34import edu.vub.at.objects.ATObject; 35import edu.vub.at.objects.grammar.ATAssignVariable; 36import edu.vub.at.objects.grammar.ATExpression; 37import edu.vub.at.objects.grammar.ATSymbol; 38import edu.vub.at.objects.natives.NATTable; 39import edu.vub.at.objects.natives.NATText; 40 41/** 42 * The native implementation of a variable assignment AG element. 43 * 44 * @author tvc 45 */ 46public final class AGAssignVariable extends NATAbstractGrammar implements ATAssignVariable { 47 48 private final ATSymbol variableName_; 49 private final ATExpression valueExp_; 50 51 public AGAssignVariable(ATSymbol nam, ATExpression val) { 52 variableName_ = nam; 53 valueExp_ = val; 54 } 55 56 public ATSymbol base_name() { return variableName_; } 57 58 public ATExpression base_valueExpression() { return valueExp_; } 59 60 /** 61 * To evaluate a variable assignment, evaluate the right hand side and ask 62 * the current object to assign that value to the field corresponding to the left hand side. 63 * 64 * AGASSVAR(nam,val).eval(ctx) = ctx.scope.assignVariable(nam, val.eval(ctx)) 65 * 66 * @return the value assigned to the variable 67 */ 68 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 69 NATTable arg = NATTable.of(valueExp_.meta_eval(ctx)); 70 ATObject result = null; 71 InvocationStack stack = InvocationStack.getInvocationStack(); 72 try { 73 stack.functionCalled(this, null, arg); 74 result = ctx.base_lexicalScope().impl_callMutator(variableName_.asAssignmentSymbol(), arg); 75 } finally { 76 stack.funcallReturned(result); 77 } 78 return result; 79 } 80 81 /** 82 * AGASSVAR(nam,val).quote(ctx) = AGASSVAR(nam.quote(ctx), val.quote(ctx)) 83 */ 84 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 85 return new AGAssignVariable(variableName_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression()); 86 } 87 88 public NATText meta_print() throws InterpreterException { 89 return NATText.atValue(variableName_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue); 90 } 91 92 public boolean isVariableAssignment() { 93 return true; 94 } 95 96 public ATAssignVariable asVariableAssignment() throws XTypeMismatch { 97 return this; 98 } 99}