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/interpreter/tags/at2dist090708/src/edu/vub/at/objects/natives/grammar/AGAssignTable.java

http://ambienttalk.googlecode.com/
Java | 101 lines | 42 code | 12 blank | 47 comment | 0 complexity | c8a5d01ccfc37ea6b93a44895e38747d MD5 | raw file
  1/**
  2 * AmbientTalk/2 Project
  3 * AGAssignTable.java created on 26-jul-2006 at 15:57:37
  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.objects.ATContext;
 32import edu.vub.at.objects.ATObject;
 33import edu.vub.at.objects.grammar.ATAssignTable;
 34import edu.vub.at.objects.grammar.ATExpression;
 35import edu.vub.at.objects.natives.NATMethodInvocation;
 36import edu.vub.at.objects.natives.NATTable;
 37import edu.vub.at.objects.natives.NATText;
 38
 39/**
 40 * The native implementation of a table assignment AG element.
 41 * 
 42 * @author tvc
 43 */
 44public final class AGAssignTable extends NATAbstractGrammar implements ATAssignTable {
 45
 46	private final ATExpression tblExp_;
 47	private final ATExpression idxExp_;
 48	private final ATExpression valExp_;
 49	
 50	public AGAssignTable(ATExpression tbl, ATExpression idx, ATExpression val) {
 51		tblExp_ = tbl;
 52		idxExp_ = idx;
 53		valExp_ = val;
 54	}
 55
 56	public ATExpression base_tableExpression() { return tblExp_; }
 57
 58	public ATExpression base_indexExpression() { return idxExp_; }
 59
 60	public ATExpression base_valueExpression() { return valExp_; }
 61	
 62	/**
 63	 * To evaluate a table assignment, evaluate its table expression to a valid ATTable.
 64	 * Next, evaluate its index expression into a valid number.
 65	 * Finally, evaluate its value expression and assign the result to the proper index slot of the table.
 66	 * 
 67	 * AGASSTABLE(tbl,idx,val).eval(ctx) =
 68	 *  tbl.eval(ctx).atPut(idx.eval(ctx), val.eval(ctx))
 69	 * 
 70	 * @return the value stored in the table
 71	 */
 72	public ATObject meta_eval(ATContext ctx) throws InterpreterException {
 73		ATObject col = tblExp_.meta_eval(ctx);
 74		ATObject idx = idxExp_.meta_eval(ctx);
 75		ATObject val = valExp_.meta_eval(ctx);
 76
 77		return col.meta_invoke(col, 
 78				new NATMethodInvocation(
 79						AGSymbol.jAlloc("atPut"), 
 80						NATTable.of(idx, val),
 81						NATTable.EMPTY));
 82	}
 83
 84	/**
 85	 * Quoting a table assignment results in a new quoted table assignment.
 86	 * 
 87	 * AGASSTABLE(tbl,idx,val).quote(ctx) = AGASSTABLE(tbl.quote(ctx),idx.quote(ctx),val.quote(ctx))
 88	 */
 89	public ATObject meta_quote(ATContext ctx) throws InterpreterException {
 90		return new AGAssignTable(tblExp_.meta_quote(ctx).asExpression(),
 91				                 idxExp_.meta_quote(ctx).asExpression(),
 92				                 valExp_.meta_quote(ctx).asExpression());
 93	}
 94	
 95	public NATText meta_print() throws InterpreterException {
 96		return NATText.atValue(tblExp_.meta_print().javaValue + "[" +
 97				idxExp_.meta_print().javaValue + "] := " +
 98				valExp_.meta_print().javaValue);
 99	}
100
101}