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The Waikato Environment for Knowledge Analysis (WEKA), a machine learning workbench. This version represents the developer version, the "bleeding edge" of development, you could say. New functionality gets added to this version.

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/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see .
 */

/*
 *    VariableDeclarationsCompositor.java
 *    Copyright (C) 2015 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.expressionlanguage.common;

import weka.core.expressionlanguage.core.Node;
import weka.core.expressionlanguage.core.VariableDeclarations;

/**
 * A helper class that allows to combine several variable declarations together.

* * It can be thought of as layering several scopes over one another.

* * It will delegate the {@link #hasVariable(String)} and {@link #getVariable(String)} * methods to other variable declarations.

* * Each variable declaration combined is checked in sequential order.

* * No checks for conflicts are done. Thus shadowing is possible.

* * @author Benjamin Weber ( benweber at student dot ethz dot ch ) * @version $Revision: 1000 $ */ public class VariableDeclarationsCompositor implements VariableDeclarations { /** the declarations being combined */ private VariableDeclarations[] declarations; /** * Constructs a {@link VariableDeclarationsCompositor} containing the provided * declarations

* * The order of the declarations will determine the order of checking the * declarations for variables.

* * @param declarations the declarations being combined */ public VariableDeclarationsCompositor(VariableDeclarations... declarations) { this.declarations = declarations; } /** * Whether the variable is contained in one of the combined declarations. * * @param name name of the variable * @return whether the variable is contained in one of the combined declarations */ @Override public boolean hasVariable(String name) { for (VariableDeclarations declaration : declarations) if (declaration.hasVariable(name)) return true; return false; } /** * Tries to fetch a variable from one of the combined declarations.

* * The same invariant of {@link VariableDeclarations} applies here too. * * @param name the name of the variable to be fetched * @return an AST (abstract syntax tree) node representing the variable */ @Override public Node getVariable(String name) { for (VariableDeclarations declaration : declarations) if (declaration.hasVariable(name)) return declaration.getVariable(name); throw new RuntimeException("Variable '" + name + "' doesn't exist!"); } }




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