/*
 * Project: MoleCuilder
 * Description: creates and alters molecular systems
 * Copyright (C)  2010 University of Bonn. All rights reserved.
 * Please see the LICENSE file or "Copyright notice" in builder.cpp for details.
 */

/**
 * \file validators.dox
 *
 * Created on: Jan 20, 2013
 *    Author: ankele
 */


/** \page validators Validators
 *
 * Validators define constraints for variables. A given variable can be
 * tested whether or not it fulfills the constraints by executing the
 * validator's isValid() function. Equivalently the Validator::operator() 
 * can be used.
 *
 * Their main purpose is to constrain user input for \ref parameters in \ref actions.
 *
 * There are several general purpose validators, for example:
 *  - DummyValidator (no constraint)
 *  - DiscreteValidator (is the variable element of a given set)
 *  - RangeValidator (is the variable inside a halfopen interval)
 *  - STLVectorValidator (defines a constraint for each element and/or for the number of elements)
 *
 * Validators can also be joined via and/or/not operations:
 * \code
 * RealSpaceMatrixSymmetricValidator() && RealSpaceMatrixInvertibleValidator()
 * \endcode
 *
 * The type of the variable is static. The base class Validator has a template 
 * parameter to define the type. Some derived validators don't have template 
 * parameters because they are derived from a Validator<SomeFixedType>.
 *
 * \date 2013-01-28
 *
 */