-- File:	NamedUnknown.cdl
-- Created:	Thu Jan 10 12:16:44 1991
-- Author:	Arnaud BOUZY
--		<adn@topsn3>
---Copyright:	 Matra Datavision 1991

class NamedUnknown from Expr

inherits NamedExpression from Expr 

    ---Purpose: This class describes any variable of an expression. 
    --          Assignment is treated directly in this class.

uses GeneralExpression from Expr, 
    Array1OfNamedUnknown from Expr,
    Array1OfReal from TColStd,
    AsciiString from TCollection

raises NotAssigned from Expr, 
    OutOfRange from Standard, 
    NumericError from Standard,
    InvalidAssignment from Expr,
    InvalidOperand from Expr,
    NotEvaluable from Expr

is

    Create(name : AsciiString)
    returns mutable NamedUnknown;

    IsAssigned(me)
    ---Purpose: Tests if an expression is assigned to <me>.
    ---C++: inline
    returns Boolean
    is static;

    AssignedExpression(me)
    ---Purpose: If exists, returns the assigned expression.
    --          An exception is raised if the expression does not exist.
    ---C++: return const &
    returns any GeneralExpression
    raises NotAssigned
    is static;

    Assign(me : mutable; exp: GeneralExpression)
    ---Purpose: Assigns <me> to <exp> expression.
    --          Raises exception if <exp> refers to <me>.
    raises InvalidAssignment
    is static;

    Deassign(me : mutable)
    ---Purpose: Supresses the assigned expression
    ---C++: inline
    is static;

    NbSubExpressions(me)
    ---Purpose: Returns the number of sub-expressions contained
    --          in <me> ( >= 0)
    returns Integer
    is static;

    SubExpression(me; I : Integer)
    ---Purpose: Returns the <I>-th sub-expression of <me>
    --          raises OutOfRange if <I> > NbSubExpressions(me)
    ---C++: return const &
    returns any GeneralExpression
    raises OutOfRange
    is static;

    Simplified(me) 
    ---Purpose: Returns a GeneralExpression after replacement of
    --          NamedUnknowns by an associated expression and after
    --          values computation.
    returns any GeneralExpression
    raises NumericError
    is static;

    ShallowSimplified(me)
    ---Purpose: Returns a GeneralExpression after a simplification 
    --          of the arguments of <me>.
    returns any GeneralExpression
    raises NumericError
    is static;

    Copy(me)
    ---Purpose: Returns a copy of <me> having the same unknowns and functions.
    returns mutable like me;
    
    ContainsUnknowns(me) 
    ---Purpose: Tests if <me> contains NamedUnknown.
    returns Boolean
    is static;

    Contains(me; exp : GeneralExpression)
    ---Purpose: Tests if <exp> is contained in <me>.
    returns Boolean
    is static;

    IsLinear(me)
    returns Boolean;

    Derivative(me; X : NamedUnknown)
    ---Purpose: Returns the derivative on <X> unknown of <me> 
    returns any GeneralExpression;

    Replace(me : mutable ; var : NamedUnknown ; with : GeneralExpression)
    ---Purpose: Replaces all occurences of <var> with <with> in <me>
    --          Raises InvalidOperand if <with> contains <me>.
    raises InvalidOperand;
    
    Evaluate(me; vars : Array1OfNamedUnknown; vals : Array1OfReal)
    ---Purpose: 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.
    returns Real
    raises NotEvaluable,NumericError;

fields

    myExpression : GeneralExpression;

end NamedUnknown;