/interpreter/tags/at_build150307/src/edu/vub/at/objects/natives/grammar/AGClosureLiteral.java

 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.NATText;
41
42/**
43 * The native implementation of a literal closure AG element.
44 * 
45 * @author tvc
46 */
47public final class AGClosureLiteral extends AGExpression implements ATClosureLiteral {
48
49	protected final ATTable arguments_;
50	protected final ATBegin body_;
51	
52	public AGClosureLiteral(ATTable args, ATBegin body) {
53		arguments_ = args;
54		body_ = body;
55	}
56	
57	public ATTable base_getArguments() { return arguments_; }
58
59	public ATBegin base_getBodyExpression() { return body_; }
60
61	/**
62	 * To evaluate a closure literal, construct a closure pairing the literal's arguments and body with the
63	 * current evaluation context.
64	 * 
65	 * AGCLOLIT(arg,bdy).eval(ctx) = AGCLO(AGMTH("lambda",arg,bdy), ctx)
66	 * 
67	 * @return a native closure closing over the current evaluation context.
68	 */
69	public ATObject meta_eval(ATContext ctx) throws InterpreterException {
70		return new NATClosure(new NATMethod(Evaluator._LAMBDA_, arguments_, body_), ctx);
71	}
72
73	/**
74	 * Quoting a closure literal results in a new quoted closure literal.
75	 * 
76	 * AGCLOLIT(arg,bdy).quote(ctx) = AGCLOLIT(arg.quote(ctx), bdy.quote(ctx))
77	 */
78	public ATObject meta_quote(ATContext ctx) throws InterpreterException {
79		return new AGClosureLiteral(arguments_.meta_quote(ctx).asTable(),
80				                   body_.meta_quote(ctx).asBegin());
81	}
82	
83	public NATText meta_print() throws InterpreterException {
84		return arguments_.base_isEmpty().base_ifTrue_ifFalse_(
85				new NativeClosure(this) {
86					public ATObject base_apply(ATTable args) throws InterpreterException {
87						return NATText.atValue("{ "+ body_.meta_print().javaValue + " }");
88					}
89				},
90				new NativeClosure(this) {
91					public ATObject base_apply(ATTable args) throws InterpreterException {
92						  return NATText.atValue(Evaluator.printElements(arguments_.asNativeTable(), "{ |", ", ", " | ").javaValue +
93			                       body_.meta_print().javaValue+"}");
94					}
95				}).asNativeText();
96	}
97	
98}