// Created on: 1991-01-10
// Created by: Arnaud BOUZY
// Copyright (c) 1991-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Expr_NamedUnknown_HeaderFile
#define _Expr_NamedUnknown_HeaderFile

#include <Standard.hxx>
#include <Standard_Type.hxx>

#include <Expr_NamedExpression.hxx>
#include <Standard_Integer.hxx>
#include <Expr_Array1OfNamedUnknown.hxx>
#include <TColStd_Array1OfReal.hxx>
class Expr_GeneralExpression;
class TCollection_AsciiString;

class Expr_NamedUnknown;
DEFINE_STANDARD_HANDLE(Expr_NamedUnknown, Expr_NamedExpression)

//! This class describes any variable of an expression.
//! Assignment is treated directly in this class.
class Expr_NamedUnknown : public Expr_NamedExpression
{

public:
  Standard_EXPORT Expr_NamedUnknown(const TCollection_AsciiString& name);

  //! Tests if an expression is assigned to <me>.
  Standard_Boolean IsAssigned() const;

  //! If exists, returns the assigned expression.
  //! An exception is raised if the expression does not exist.
  Standard_EXPORT const Handle(Expr_GeneralExpression)& AssignedExpression() const;

  //! Assigns <me> to <exp> expression.
  //! Raises exception if <exp> refers to <me>.
  Standard_EXPORT void Assign(const Handle(Expr_GeneralExpression)& exp);

  //! Suppresses the assigned expression
  void Deassign();

  //! Returns the number of sub-expressions contained
  //! in <me> ( >= 0)
  Standard_EXPORT Standard_Integer NbSubExpressions() const Standard_OVERRIDE;

  //! Returns the <I>-th sub-expression of <me>
  //! raises OutOfRange if <I> > NbSubExpressions(me)
  Standard_EXPORT const Handle(Expr_GeneralExpression)& SubExpression(
    const Standard_Integer I) const Standard_OVERRIDE;

  //! Returns a GeneralExpression after replacement of
  //! NamedUnknowns by an associated expression and after
  //! values computation.
  Standard_EXPORT Handle(Expr_GeneralExpression) Simplified() const Standard_OVERRIDE;

  //! Returns a GeneralExpression after a simplification
  //! of the arguments of <me>.
  Standard_EXPORT Handle(Expr_GeneralExpression) ShallowSimplified() const Standard_OVERRIDE;

  //! Returns a copy of <me> having the same unknowns and functions.
  Standard_EXPORT Handle(Expr_GeneralExpression) Copy() const Standard_OVERRIDE;

  //! Tests if <me> contains NamedUnknown.
  Standard_EXPORT Standard_Boolean ContainsUnknowns() const Standard_OVERRIDE;

  //! Tests if <exp> is contained in <me>.
  Standard_EXPORT Standard_Boolean
    Contains(const Handle(Expr_GeneralExpression)& exp) const Standard_OVERRIDE;

  Standard_EXPORT Standard_Boolean IsLinear() const Standard_OVERRIDE;

  //! Returns the derivative on <X> unknown of <me>
  Standard_EXPORT Handle(Expr_GeneralExpression) Derivative(
    const Handle(Expr_NamedUnknown)& X) const Standard_OVERRIDE;

  //! Replaces all occurrences of <var> with <with> in <me>
  //! Raises InvalidOperand if <with> contains <me>.
  Standard_EXPORT void Replace(const Handle(Expr_NamedUnknown)&      var,
                               const Handle(Expr_GeneralExpression)& with) Standard_OVERRIDE;

  //! Returns the value of <me> (as a Real) by
  //! replacement of <vars> by <vals>.
  //! Raises NotEvaluable if <me> contains NamedUnknown not
  //! in <vars> or NumericError if result cannot be computed.
  Standard_EXPORT Standard_Real Evaluate(const Expr_Array1OfNamedUnknown& vars,
                                         const TColStd_Array1OfReal& vals) const Standard_OVERRIDE;

  DEFINE_STANDARD_RTTIEXT(Expr_NamedUnknown, Expr_NamedExpression)

protected:
private:
  Handle(Expr_GeneralExpression) myExpression;
};

#include <Expr_NamedUnknown.lxx>

#endif // _Expr_NamedUnknown_HeaderFile
