/interpreter/tags/at2dist041108/src/edu/vub/at/objects/natives/grammar/AGMultiAssignment.java
Java | 121 lines | 53 code | 16 blank | 52 comment | 6 complexity | 0c77da763fbf8b0add8442c290e5bfc4 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGMultiAssignment.java created on 18-aug-2006 at 9:31:38 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.PartialBinder; 31import edu.vub.at.exceptions.InterpreterException; 32import edu.vub.at.objects.ATContext; 33import edu.vub.at.objects.ATObject; 34import edu.vub.at.objects.ATTable; 35import edu.vub.at.objects.grammar.ATExpression; 36import edu.vub.at.objects.grammar.ATMultiAssignment; 37import edu.vub.at.objects.natives.NATText; 38 39import java.util.HashSet; 40import java.util.Set; 41 42/** 43 * @author tvc 44 * 45 * The native implementation of a multiple assignment AG element. 46 */ 47public final class AGMultiAssignment extends NATAbstractGrammar implements ATMultiAssignment { 48 49 private final ATTable parameters_; 50 private final ATExpression valueExp_; 51 52 private final PartialBinder binderPartialFunction_; 53 54 public AGMultiAssignment(ATTable par, ATExpression val) throws InterpreterException { 55 parameters_ = par; 56 valueExp_ = val; 57 binderPartialFunction_ = PartialBinder.calculateResidual("multi-assignment", par); 58 } 59 60 public ATTable base_parameters() { return parameters_; } 61 62 public ATExpression base_valueExpression() { return valueExp_; } 63 64 /** 65 * To evaluate a multiple assignment, evaluate the right hand side to a table 66 * and assign the parameters on the left hand side to the 'arguments' of the right hand side, 67 * almost as if they were bound during a function call (the parameters are assigned instead of defined). 68 * 69 * AGMULTIASS(par,val).eval(ctx) = assign(ctx.scope, par, val.eval(ctx)) 70 * 71 * @return the evaluated arguments table 72 */ 73 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 74 ATTable args = valueExp_.meta_eval(ctx).asTable(); 75 PartialBinder.assignArgsToParams(binderPartialFunction_, ctx, args); 76 return args; 77 } 78 79 /** 80 * AGMULTIASS(par,val).quote(ctx) = AGMULTIASS(par.quote(ctx), val.quote(ctx)) 81 */ 82 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 83 return new AGMultiAssignment(parameters_.meta_quote(ctx).asTable(), valueExp_.meta_quote(ctx).asExpression()); 84 } 85 86 public NATText meta_print() throws InterpreterException { 87 return NATText.atValue(parameters_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue); 88 } 89 90 /** 91 * FV([var1, var2 := exp1, @ rest] := exp2) = 92 * { var1, var2, rest } U FV(exp1) U FV(exp2) 93 */ 94 public Set impl_freeVariables() throws InterpreterException { 95 Set fvValExp = valueExp_.impl_freeVariables(); 96 97 ATObject[] params = parameters_.asNativeTable().elements_; 98 for (int i = 0; i < params.length; i++) { 99 if (params[i].isSymbol()) { 100 // Mandatory arguments, e.g. x 101 fvValExp.add(params[i].asSymbol()); 102 } else if (params[i].isVariableAssignment()) { 103 // Optional args or rest args 104 // Note: for optional args, both assigned var and free vars 105 // of the initialization expression are considered free vars 106 fvValExp.addAll(params[i].asExpression().impl_freeVariables()); 107 } else if (params[i].isSplice()) { 108 fvValExp.add(params[i].asSplice().base_expression().asSymbol()); 109 } 110 } 111 return fvValExp; 112 } 113 114 115 public Set impl_quotedFreeVariables() throws InterpreterException { 116 Set qfv = parameters_.impl_quotedFreeVariables(); 117 qfv.addAll(valueExp_.impl_quotedFreeVariables()); 118 return qfv; 119 } 120 121}