-- File:	UnknownIterator.cdl
-- Created:	Wed Sep 18 09:56:26 1991
-- Author:	Arnaud BOUZY
--		<adn@topsn2>
---Copyright:	 Matra Datavision 1991


class UnknownIterator from Expr 

	---Purpose: Describes an iterator on NamedUnknowns contained 
	--          in any GeneralExpression.
        ---Level : Internal

uses GeneralExpression from Expr,
    NamedUnknown from Expr,
    MapOfNamedUnknown from Expr

raises NoMoreObject from Standard,
    NoSuchObject from Standard

is

    Create(exp : GeneralExpression)
    returns UnknownIterator;
    
    Perform(me: in out; exp : GeneralExpression)
    is static private;
    
    More(me)
    returns Boolean
    is static;
    
    Next(me : in out)
    raises NoMoreObject
    is static;
    
    Value(me)
    returns NamedUnknown
    raises NoSuchObject
    is static;

fields

    myMap : MapOfNamedUnknown;
    myCurrent : Integer;

end UnknownIterator;