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

 1/**
 2 * AmbientTalk/2 Project
 3 * AGSplice.java created on 1-aug-2006 at 21:12:15
 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.XIllegalSplice;
32import edu.vub.at.exceptions.XTypeMismatch;
33import edu.vub.at.objects.ATContext;
34import edu.vub.at.objects.ATObject;
35import edu.vub.at.objects.grammar.ATExpression;
36import edu.vub.at.objects.grammar.ATSplice;
37import edu.vub.at.objects.natives.NATText;
38
39/**
40 * @author tvc
41 *
42 * The native implementation of an AGSplice AG element.
43 */
44public class AGSplice extends AGExpression implements ATSplice {
45
46	private final ATExpression splExp_;
47	
48	public AGSplice(ATExpression exp) {
49		splExp_ = exp;
50	}
51	
52	public ATExpression base_getExpression() { return splExp_; }
53
54	/**
55	 * A spliced element cannot be evaluated, but rather gives rise to an XIllegalSplice exception.
56	 * This is because a splice should always be nested within either a formal parameter list or a table.
57	 * 
58	 * AGSPL(exp).eval(ctx) = ERROR
59	 */
60	public ATObject meta_eval(ATContext ctx) throws InterpreterException {
61		throw new XIllegalSplice(splExp_);
62	}
63
64	/**
65	 * Quoting a splice means quoting its contained expression, and returning a new splice.
66	 */
67	public ATObject meta_quote(ATContext ctx) throws InterpreterException {
68		return new AGSplice(splExp_.meta_quote(ctx).asExpression());
69	}
70
71	public NATText meta_print() throws InterpreterException {
72		return NATText.atValue("@"+ splExp_.meta_print().javaValue);
73	}
74
75	public boolean isSplice() { return true; }
76	
77	public ATSplice asSplice() throws XTypeMismatch {
78		return this;
79	}
80
81}