UserExpression.h

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// ========================================================================= //
// This file is part of MyraMath, copyright (c) 2014-2019 by Ryan A Chilton  //
// and distributed by MyraCore, LLC. See LICENSE.txt for license terms.      //
// ========================================================================= //

#ifndef MYRAMATH_EXPRESSION_USEREXPRESSION_H
#define MYRAMATH_EXPRESSION_USEREXPRESSION_H

#include <myramath/utility/Number.h>
#include <myramath/expression/Expression.h>
#include <myramath/expression/ExpressionBase.h>

namespace myra {
namespace detail {

// Implementation detail.
template<class UserClass> class UserExpression : public ExpressionBase<UserClass::Arity,typename UserClass::Number>
  {
  public:

    // Reflect the Arity and Number type, both must be present in the user's class.
    const static int Arity = UserClass::Arity;
    typedef typename UserClass::Number Number;

    // Constructor, requires a copy constructible UserClass.
    UserExpression(const UserClass& in_u)
      : u(in_u) { }

  protected:

    virtual Index<Arity> size() const
      { return u.size(); }
  
    virtual Number evaluate(Index<Arity> i) const
      { return u.evaluate(i); }
    
    // Virtual copy constructor.
    virtual ExpressionBase<Arity,Number>* clone() const
      { return new UserExpression<UserClass>(u); }
    
  private:
  
    // Deep copy of user's class.
    UserClass u;
    
  };

} // namespace detail

template<class UserClass> Expression<UserClass::Arity,typename UserClass::Number>  make_UserExpression(const UserClass& u)
  { return detail::UserExpression<UserClass>(u); }

} // namespace myra

#endif