/interpreter/tags/at2dist030708/src/edu/vub/at/objects/natives/grammar/AGClosureLiteral.java
Java | 108 lines | 48 code | 11 blank | 49 comment | 2 complexity | 75ca53195f326d996d6fb8cb0d4d26c1 MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * AGClosureLiteral.java created on 26-jul-2006 at 16:59:04 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.Evaluator; 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.ATBegin; 36import edu.vub.at.objects.grammar.ATClosureLiteral; 37import edu.vub.at.objects.mirrors.NativeClosure; 38import edu.vub.at.objects.natives.NATClosure; 39import edu.vub.at.objects.natives.NATMethod; 40import edu.vub.at.objects.natives.NATTable; 41import edu.vub.at.objects.natives.NATText; 42 43/** 44 * The native implementation of a literal closure AG element. 45 * 46 * @author tvc 47 */ 48public final class AGClosureLiteral extends AGExpression implements ATClosureLiteral { 49 50 protected final ATTable arguments_; 51 protected final ATBegin body_; 52 53 private NATMethod preprocessedMethod_; 54 55 public AGClosureLiteral(ATTable args, ATBegin body) throws InterpreterException { 56 arguments_ = args; 57 body_ = body; 58 } 59 60 public ATTable base_arguments() { return arguments_; } 61 62 public ATBegin base_bodyExpression() { return body_; } 63 64 /** 65 * To evaluate a closure literal, construct a closure pairing the literal's arguments and body with the 66 * current evaluation context. 67 * 68 * AGCLOLIT(arg,bdy).eval(ctx) = AGCLO(AGMTH("lambda",arg,bdy), ctx) 69 * 70 * @return a native closure closing over the current evaluation context. 71 */ 72 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 73 // the method is not yet created in the constructor because this gives problems 74 // with quoted parameters: a quoted parameter would result in an illegal parameter 75 // exception while actually the block was defined in the context of a quotation, 76 // so at runtime the block would have never been evaluated (but quoted instead) 77 if (preprocessedMethod_ == null) { 78 preprocessedMethod_ = new NATMethod(Evaluator._LAMBDA_, arguments_, body_, NATTable.EMPTY); 79 } 80 return new NATClosure(preprocessedMethod_, ctx); 81 } 82 83 /** 84 * Quoting a closure literal results in a new quoted closure literal. 85 * 86 * AGCLOLIT(arg,bdy).quote(ctx) = AGCLOLIT(arg.quote(ctx), bdy.quote(ctx)) 87 */ 88 public ATObject meta_quote(ATContext ctx) throws InterpreterException { 89 return new AGClosureLiteral(arguments_.meta_quote(ctx).asTable(), 90 body_.meta_quote(ctx).asBegin()); 91 } 92 93 public NATText meta_print() throws InterpreterException { 94 return arguments_.base_isEmpty().base_ifTrue_ifFalse_( 95 new NativeClosure(this) { 96 public ATObject base_apply(ATTable args) throws InterpreterException { 97 return NATText.atValue("{ "+ body_.meta_print().javaValue + " }"); 98 } 99 }, 100 new NativeClosure(this) { 101 public ATObject base_apply(ATTable args) throws InterpreterException { 102 return NATText.atValue(Evaluator.printElements(arguments_.asNativeTable(), "{ |", ", ", " | ").javaValue + 103 body_.meta_print().javaValue+"}"); 104 } 105 }).asNativeText(); 106 } 107 108}