001/* Token that contains a function.
002
003 Copyright (c) 2003-2014 The Regents of the University of California.
004 All rights reserved.
005 Permission is hereby granted, without written agreement and without
006 license or royalty fees, to use, copy, modify, and distribute this
007 software and its documentation for any purpose, provided that the above
008 copyright notice and the following two paragraphs appear in all copies
009 of this software.
010
011 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
012 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
013 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
014 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
015 SUCH DAMAGE.
016
017 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
018 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
019 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
020 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
021 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
022 ENHANCEMENTS, OR MODIFICATIONS.
023
024 PT_COPYRIGHT_VERSION_2
025 COPYRIGHTENDKEY
026
027 */
028package ptolemy.data;
029
030import ptolemy.kernel.util.IllegalActionException;
031
032//////////////////////////////////////////////////////////////////////////
033//// FunctionToken
034
035/** The interface for functions contained by function tokens.
036
037 @author Xiaojun Liu, Steve Neuendorffer
038 @version $Id$
039 @since Ptolemy II 4.0
040 @Pt.ProposedRating Yellow (liuxj)
041 @Pt.AcceptedRating Red (liuxj)
042 */
043public interface Function {
044    /** Apply the function to the list of arguments, which are tokens.
045     *  @param arguments The list of arguments.
046     *  @return The result of applying the function to the given
047     *   arguments.
048     *  @exception IllegalActionException If thrown during evaluating
049     *   the function.
050     */
051    public Token apply(Token[] arguments) throws IllegalActionException;
052
053    /** Return the number of arguments of the function.
054     *  @return The number of arguments of the function.
055     */
056    public int getNumberOfArguments();
057
058    /** Return true if this function is congruent to the given
059     *  function.  Classes should implement this method so that
060     *  two functions are congruent under any renaming of the
061     *  bound variables of the function.  For simplicity, a
062     *  function need only be congruent to other functions of the
063     *  same class.
064     *  @param function The function to check congruency against.
065     *  @return True if this function is congruent with the given function.
066     */
067    public boolean isCongruent(Function function);
068
069    /** Return a string representation.
070     *  @return A string representation of this function.
071     */
072    @Override
073    public String toString();
074}