-- File:	IFSelect_ModelModifier.cdl
-- Created:	Mon Mar 21 16:07:03 1994
-- Author:	Christian CAILLET
--		<cky@ecolox>
---Copyright:	 Matra Datavision 1994


deferred generic class  ModelModifier  from IFSelect
    	(Model    as InterfaceModel; Proto as Protocol from Interface)
    inherits Modifier

    ---Purpose : Allows to precise the frame work for Model Modifiers able to
    --           run with an Interface (such as STEP, VDA, IGES ...)
    --           
    --           Acts as a Modifier but properly casts Model and Protocol
    --           according to each Interface, and refuses to work if cast
    --           has failed (i.e. if it is not used in good context)
    --           
    --           Then, it is finer to make specific Model Modifier inherit
    --           from an instantiated ModelModifier, instead of Modifier itself
    --           (though it is not mandatory)
    --           
    --           For each Interface on which Model Modifiers have to be defined,
    --           The way to follow is firstly to instantiate ModelModifier with
    --           its specific data :
    --           Model is the InterfaceModel specific to the considered norm
    --           Then to define the various classes which inherit from it and
    --           define their method Perform

uses CString, InterfaceModel, Protocol from Interface,  CopyTool, ContextModif

is

    Initialize (maychangegraph : Boolean);
    ---Purpose : Calls inherited Initialize, transmits to it the information
    --           <maychangegraph>

    Perform (me; ctx  : in out ContextModif;
    	     target   : mutable InterfaceModel;
    	     protocol : Protocol from Interface;
    	     TC       : in out CopyTool);
    ---Purpose : The inherited Perform does the required cast (and refuses to
    --           go further if cast has failed) then calls the instantiated
    --           Performing

    PerformProtocol (me; ctx : in out ContextModif;
    	     target : mutable Model;
    	     proto  : Proto;
    	     TC     : in out CopyTool)  is virtual;
    ---Purpose : Specific Perform with Protocol. It is defined to let the
    --           Protocol unused and to call Performing without Protocol
    --           (most current case). It can be redefined if specific action
    --           requires Protocol.

    Performing (me; ctx : in out ContextModif;
    	     target : mutable Model;
    	     TC     : in out CopyTool)  is deferred;
    ---Purpose : Specific Perform, without Protocol. If Performing with
    --           Protocol is redefined, Performing without Protocol must
    --           though be defined to do nothing (not called, but demanded
    --           by the linker)

end ModelModifier;