-- File:	SystemRelation.cdl
-- Created:	Mon Jan 14 09:50:50 1991
-- Author:	Arnaud BOUZY
--		<adn@topsn3>
---Copyright:	 Matra Datavision 1991

class SystemRelation from Expr

inherits GeneralRelation from Expr

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

raises OutOfRange,NoSuchObject,DimensionMismatch,NumericError

is

    Create(relation : GeneralRelation)
    ---Purpose: Creates a system with one relation
    ---Level : Advanced
    returns mutable SystemRelation;

    Add(me : mutable; relation : GeneralRelation)
    ---Purpose: Appends <relation> in the list of components of <me>. 
    ---Level : Advanced
    is static;
    
    Remove(me : mutable; relation : GeneralRelation)
    ---Level : Internal
    raises NoSuchObject,DimensionMismatch
    is static;

    IsLinear(me)
    ---Purpose: Tests if <me> is linear between its NamedUnknowns.
    returns Boolean
    is static;

    NbOfSubRelations(me)
    ---Purpose: Returns the number of relations contained in <me>.
    returns Integer
    is static;

    NbOfSingleRelations(me)
    ---Purpose: Returns the number of SingleRelations contained in 
    --          <me>.
    returns Integer
    is static;

    SubRelation(me; index : Integer)
    ---Purpose: Returns the relation denoted by <index> in <me>.
    --          An exception is raised if <index> is out of range.
    returns any GeneralRelation
    raises OutOfRange
    is static;

    IsSatisfied(me)
    returns Boolean;

    Simplified(me)
    ---Purpose: Returns a GeneralRelation after replacement of
    --          NamedUnknowns by an associated expression, and after
    --          values computation.
    returns mutable GeneralRelation
    raises NumericError;
    
    Simplify(me : mutable)
    ---Purpose: Replaces NamedUnknowns by associated expressions,
    --          and computes values in <me>.
    raises NumericError;

    Copy(me)
    ---Purpose: Returns a copy of <me> having the same unknowns and functions.
    returns mutable like me;
    
    Contains(me; exp : GeneralExpression)
    ---Purpose: Tests if <me> contains <exp>.
    returns Boolean;
    
    Replace(me : mutable ; var : NamedUnknown ; with : GeneralExpression);
    ---Purpose: Replaces all occurences of <var> with <with> in <me>.
    
    String(me)
    ---Purpose: returns a string representing <me> in a readable way.
    returns AsciiString;
    
fields

    myRelations : SequenceOfGeneralRelation;
    

end SystemRelation;