/interpreter/tags/at2dist170907/src/edu/vub/at/objects/natives/grammar/AGDefTable.java
Java | 123 lines | 54 code | 14 blank | 55 comment | 1 complexity | 84e8b49122b10179c3c0ef9ed2f19cc2 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGDefTable.java created on 26-jul-2006 at 15:50:45 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.XIllegalIndex; 32import edu.vub.at.exceptions.XTypeMismatch; 33import edu.vub.at.objects.ATContext; 34import edu.vub.at.objects.ATObject; 35import edu.vub.at.objects.grammar.ATBegin; 36import edu.vub.at.objects.grammar.ATDefTable; 37import edu.vub.at.objects.grammar.ATExpression; 38import edu.vub.at.objects.grammar.ATSymbol; 39import edu.vub.at.objects.natives.NATCallframe; 40import edu.vub.at.objects.natives.NATTable; 41import edu.vub.at.objects.natives.NATText; 42 43/** 44 * @author tvc 45 * 46 * The native implementation of a table definition AG element. 47 */ 48public final class AGDefTable extends NATAbstractGrammar implements ATDefTable { 49 50 private final ATSymbol tblName_; 51 private final ATExpression sizExp_; 52 private final ATBegin initExp_; 53 54 public AGDefTable(ATSymbol nam, ATExpression siz, ATBegin ini) { 55 tblName_ = nam; 56 sizExp_ = siz; 57 initExp_ = ini; 58 } 59 60 public ATSymbol base_name() { return tblName_; } 61 62 public ATExpression base_sizeExpression() { return sizExp_; } 63 64 public ATBegin base_initializer() { return initExp_; } 65 66 /** 67 * Defining a table requires evaluating its index expression to a size s, 68 * then allocating a new table of size s and finally initializing it 69 * by evaluating its initializer body s times. The return value is the defined table. 70 * 71 * The initializer body is evaluated in a new scope, so definitions inside the initializer 72 * are not visible to the outside (table defining) scope. 73 * 74 * AGDEFTABLE(nam,siz,ini).eval(ctx) = 75 * s = siz.eval(ctx) 76 * t[s] = nil 77 * inictx = ctx[cur -> callframe(ctx.cur)] 78 * i.from: 0 to: s do: { 79 * t[i] := ini.eval(ctx) 80 * } 81 * ctx.scope.defineField(nam, AGTABLE(t)) 82 * AGTABLE(t) 83 */ 84 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 85 int siz = 0; 86 try { 87 siz = sizExp_.meta_eval(ctx).asNativeNumber().javaValue; 88 } catch (XTypeMismatch e) { 89 throw new XIllegalIndex(e.getMessage()); 90 } 91 92 NATCallframe initscope = new NATCallframe(ctx.base_lexicalScope()); 93 ATContext initctx = ctx.base_withLexicalEnvironment(initscope); 94 ATObject[] tab = new ATObject[siz]; 95 for (int i = 0; i < tab.length; i++) { 96 tab[i] = initExp_.meta_eval(initctx); 97 } 98 99 NATTable tbl = NATTable.atValue(tab); 100 ctx.base_lexicalScope().meta_defineField(tblName_, tbl); 101 102 return tbl; 103 } 104 105 /** 106 * Quoting a table definition results in a new quoted table definition. 107 * 108 * AGDEFTABLE(nam,siz,ini).quote(ctx) = AGDEFTABLE(nam.quote(ctx), siz.quote(ctx), ini.quote(ctx)) 109 */ 110 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 111 return new AGDefTable(tblName_.meta_quote(ctx).asSymbol(), 112 sizExp_.meta_quote(ctx).asExpression(), 113 initExp_.meta_quote(ctx).asBegin()); 114 } 115 116 public NATText meta_print() throws InterpreterException { 117 return NATText.atValue("def " + 118 tblName_.meta_print().javaValue + "[" + 119 sizExp_.meta_print().javaValue + "] { " + 120 initExp_.meta_print().javaValue + "}"); 121 } 122 123}