-- File:	BinaryExpression.cdl
-- Created:	Thu Jan 10 12:27:32 1991
-- Author:	Arnaud BOUZY
--		<adn@topsn3>
---Copyright:	 Matra Datavision 1991

deferred class BinaryExpression from Expr
    
inherits GeneralExpression from Expr
    ---Purpose: Defines all binary expressions. The order of the two 
    --          operands is significant.

uses NamedUnknown from Expr
    
raises OutOfRange from Standard,
    NumericError from Standard,
    InvalidOperand from Expr

is

    FirstOperand(me)
    ---C++: inline
    ---C++: return const &
    ---Level : Internal
    returns any GeneralExpression
    is static;

    SecondOperand(me)
    ---C++: inline
    ---C++: return const &
    ---Level : Internal
    returns any GeneralExpression
    is static;

    SetFirstOperand(me : mutable; exp : GeneralExpression)
    ---Purpose: Sets first operand of <me>
    --          Raises InvalidOperand if exp = me
    ---Level : Internal
    raises InvalidOperand
    is static;

    SetSecondOperand(me : mutable; exp : GeneralExpression)
    ---Purpose: Sets second operand of <me>
    --          Raises InvalidOperand if <exp> contains <me>.
    ---Level : Internal
    raises InvalidOperand
    is static;

    CreateFirstOperand(me : mutable; exp : GeneralExpression)
    ---Purpose: Sets first operand of <me>
    ---Level : Internal
    is static protected;

    CreateSecondOperand(me : mutable; exp : GeneralExpression)
    ---Purpose: Sets second operand of <me>
    --          Raises InvalidOperand if <exp> contains <me>.
    ---Level : Internal
    is static protected;

    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;

    ContainsUnknowns(me) 
    ---Purpose: Does <me> contain NamedUnknown ?
    returns Boolean
    is static;

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

    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
    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;
    
fields

    myFirstOperand  : GeneralExpression;
    mySecondOperand : GeneralExpression;

end BinaryExpression;