/interpreter/tags/at2dist091109/src/edu/vub/at/objects/natives/grammar/AGAssignTable.java

  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
 39import java.util.Set;
 40
 41/**
 42 * The native implementation of a table assignment AG element.
 43 * 
 44 * @author tvc
 45 */
 46public final class AGAssignTable extends NATAbstractGrammar implements ATAssignTable {
 47
 48	private final ATExpression tblExp_;
 49	private final ATExpression idxExp_;
 50	private final ATExpression valExp_;
 51	
 52	public AGAssignTable(ATExpression tbl, ATExpression idx, ATExpression val) {
 53		tblExp_ = tbl;
 54		idxExp_ = idx;
 55		valExp_ = val;
 56	}
 57
 58	public ATExpression base_tableExpression() { return tblExp_; }
 59
 60	public ATExpression base_indexExpression() { return idxExp_; }
 61
 62	public ATExpression base_valueExpression() { return valExp_; }
 63	
 64	/**
 65	 * To evaluate a table assignment, evaluate its table expression to a valid ATTable.
 66	 * Next, evaluate its index expression into a valid number.
 67	 * Finally, evaluate its value expression and assign the result to the proper index slot of the table.
 68	 * 
 69	 * AGASSTABLE(tbl,idx,val).eval(ctx) =
 70	 *  tbl.eval(ctx).atPut(idx.eval(ctx), val.eval(ctx))
 71	 * 
 72	 * @return the value stored in the table
 73	 */
 74	public ATObject meta_eval(ATContext ctx) throws InterpreterException {
 75		ATObject col = tblExp_.meta_eval(ctx);
 76		ATObject idx = idxExp_.meta_eval(ctx);
 77		ATObject val = valExp_.meta_eval(ctx);
 78
 79		return col.meta_invoke(col, 
 80				new NATMethodInvocation(
 81						AGSymbol.jAlloc("atPut"), 
 82						NATTable.of(idx, val),
 83						NATTable.EMPTY));
 84	}
 85
 86	/**
 87	 * Quoting a table assignment results in a new quoted table assignment.
 88	 * 
 89	 * AGASSTABLE(tbl,idx,val).quote(ctx) = AGASSTABLE(tbl.quote(ctx),idx.quote(ctx),val.quote(ctx))
 90	 */
 91	public ATObject meta_quote(ATContext ctx) throws InterpreterException {
 92		return new AGAssignTable(tblExp_.meta_quote(ctx).asExpression(),
 93				                 idxExp_.meta_quote(ctx).asExpression(),
 94				                 valExp_.meta_quote(ctx).asExpression());
 95	}
 96	
 97	public NATText meta_print() throws InterpreterException {
 98		return NATText.atValue(tblExp_.meta_print().javaValue + "[" +
 99				idxExp_.meta_print().javaValue + "] := " +
100				valExp_.meta_print().javaValue);
101	}
102	
103
104	/**
105	 * FV(tblExp[idxExp] := valExp) = FV(tblExp) U FV(idxExp) U FV(valExp)
106	 */
107	public Set impl_freeVariables() throws InterpreterException {
108		Set fvTblExp = tblExp_.impl_freeVariables();
109		fvTblExp.addAll(idxExp_.impl_freeVariables());
110		fvTblExp.addAll(valExp_.impl_freeVariables());
111		return fvTblExp;
112	}
113	
114	public Set impl_quotedFreeVariables() throws InterpreterException {
115		Set qfv = tblExp_.impl_quotedFreeVariables();
116		qfv.addAll(idxExp_.impl_quotedFreeVariables());
117		qfv.addAll(valExp_.impl_quotedFreeVariables());
118		return qfv;
119	}
120
121}