-- File:	GeneralRelation.cdl
-- Created:	Mon Jan 14 09:44:03 1991
-- Author:	Arnaud BOUZY
--		<adn@topsn3>
---Copyright:	 Matra Datavision 1991

deferred class GeneralRelation from Expr
    
inherits TShared from MMgt 

    ---Purpose: Defines the general purposes of any relation between 
    --          expressions.

uses GeneralExpression from Expr,
    NamedUnknown from Expr,
    AsciiString from TCollection


raises OutOfRange from Standard,
    NumericError from Standard

is

    IsSatisfied(me)
    ---Purpose: Returns the current status of the relation
    ---Level: Advanced 
    returns Boolean
    is deferred;

    IsLinear(me)
    ---Purpose: Tests if <me> is linear between its NamedUnknowns.
    ---Level: Advanced 
    returns Boolean
    is deferred;
    
    Simplified(me)
    ---Purpose: Returns a GeneralRelation after replacement of
    --          NamedUnknowns by an associated expression, and after
    --          values computation.
    ---Level: Advanced 
    returns mutable GeneralRelation
    raises NumericError
    is deferred;

    Simplify(me : mutable)
    ---Purpose: Replaces NamedUnknowns by associated expressions,
    --          and computes values in <me>.
    ---Level: Advanced 
    raises NumericError
    is deferred;
    
    Copy(me)
    ---Purpose: Returns a copy of <me> having the same unknowns and 
    --          functions.
    ---Level: Advanced 
    returns mutable like me
    is deferred;
    
    NbOfSubRelations(me)
    ---Purpose: Returns the number of relations contained in <me>.
    ---Level: Internal
    returns Integer
    is deferred;
    
    NbOfSingleRelations(me)
    ---Purpose: Returns the number of SingleRelations contained in 
    --          <me>.
    ---Level: Internal
    returns Integer
    is deferred;
    
    SubRelation(me; index : Integer)
    ---Purpose: Returns the relation denoted by <index> in <me>.
    --          An exception is raised if <index> is out of range.
    ---Level: Internal
    returns any GeneralRelation
    raises OutOfRange
    is deferred;

    Contains(me; exp : GeneralExpression)
    ---Purpose: Tests if <exp> contains <var>.
    ---Level: Internal
    returns Boolean
    is deferred;
    
    Replace(me : mutable ; var : NamedUnknown ; with : GeneralExpression)
    ---Purpose: Replaces all occurences of <var> with <with> in <me>.
    ---Level: Internal
    is deferred;
    
    String(me)
    ---Purpose: returns a string representing <me> in a readable way.
    ---Level: Public
    returns AsciiString
    is deferred;
    
end GeneralRelation;