Hi again,
Maybe it helps if you define a seperate type for the content of your model.
Something like:
ModelInfo = POINTER TO RECORD
predictors*: Predictor;
rank*, unsuitable*: XYCoord;
labels*, medians*, ass1*: XYCoord;
prev*, next*: ModelInfo
END;
Model* = POINTER TO RECORD (Models.Model)
root*: ModelInfo
END;
If you break out the contents of the model into its own data structure, then
you can define your model as a POINTER TO RECORD but still manipulate the
list. That is, you can now define methods in the Model type, that takes VAR
parameters of type ModelInfo as input.
This is exactly what the ObxLines example does. I think this Obx example can
be very helpful to you.
Bengt
> -----Original Message-----
> From: Mary Kynn [mailto:m.kynn{([at]})nowhere.xy> Sent: Mittwoch, 23. August 2000 02:39
> To: Bengt Johansson
> Cc: Marc Frei; BlackBox{([at]})nowhere.xy
> Subject: RE: RECORD vs POINTER TO RECORD
>
>
> Hi,
>
> sorry I didn't make myself clear. I originally defined my model as
> follows:
>
> TYPE
> Name* = ARRAY 12 OF CHAR;
>
> Coord* = RECORD (Stores.Store)
> l*, t*, r*, b*: INTEGER;
> END;
>
> XYCoord* = POINTER TO RECORD (Models.Model)
> name*: Name;
> x*, y*: INTEGER;
> next*: XYCoord
> END;
>
> Predictor* = RECORD
> name* : ARRAY 32 OF CHAR;
> predtype*: INTEGER;
> rangefrom*, rangeto*: REAL;
> rangelevels*: INTEGER;
> optcont*: REAL ;
> END;
>
> Model* = POINTER TO RECORD (Models.Model)
> predictors*: Predictor;
> rank*, unsuitable*: XYCoord;
> labels*, medians*, ass1*: XYCoord;
> prev*, next*: Model
> END;
>
> MoveOperation = POINTER TO RECORD (Stores.Operation)
> dy: INTEGER; (*Change vertical
> component. Left
> and right do not change.*)
> model: Model;
> fig: XYCoord
> END;
>
> NameOperation = POINTER TO RECORD (Stores.Operation)
> newname: Name; (*Change name of
> (rank) variable....would work for any XYCoord*)
> model: Model;
> rank: XYCoord
> END;
>
> UpdateMsg* = RECORD (Models.UpdateMsg)
> y*: INTEGER
> END;
>
> UpdateNameMsg* = RECORD (Models.UpdateMsg)
> name*: Name
> END;
>
> VAR
> interactor*: Predictor;
> header*, current*: Model; (* header (or root) and current elements
> of doubly-linked ring *)
> location: Files.Locator;
> filename: Files.Name;
> bg* (*background coordinates*): Coord;
> optmedian*, optquartiles*(*assessment when ALL variables and
> factors at optimum*): XYCoord;
>
> With the model defined this way I can only have have one instance of the
> model running as it requires the VAR interactor, header, current etc (and
> I am also having trouble with PropogateDomain- , so I can't cut/copy and
> paste the views associated with this model). So I want to redefine the
> model so it incorporates ALL the necessary variables and use it as a
> class. I have tried to do this like this:
>
> Figure* = POINTER TO RECORD (Stores.Store)
> name*: Name;
> x*, y*: INTEGER;
> next*: Figure
> END;
>
> Predictor* = POINTER TO RECORD (Stores.Store)
> name* : ARRAY 32 OF CHAR;
> predtype*: INTEGER;
> rangefrom*, rangeto*: REAL;
> rangelevels*: INTEGER;
> optcont*: REAL ;
> rank*, unsuitable*: Figure;
> labels*, medians*, ass1*, ass2*, ass3*: Figure;
> prev*, next*: Predictor
> END;
>
> Model* = RECORD (Models.Model)
> current*, header* : Predictor;
> bg*: Coord; (*background coordinates*)
> optmedian*, optquartiles*: Figure (*assessmentwhen ALL
> variables and factors at optimum*)
> END;
>
> I wanted to define the model as a RECORD not a POINTER TO RECORD becuase I
> can't call a pointer by reference in the receiver of a method. Is this
> possible? If its not, the procedures that operate on the data cannot be
> methods of the class?
>
> sorry for the lengthy email, I would be very appreciative of any advice.
>
> regards,
> Mary Kynn.
>
> On Tue, 22 Aug 2000, Bengt Johansson wrote:
>
> >
> > Hi Mary,
> >
> > We don't fully understand what you would like to do. However,
> the ObxLines
> > example might be helpful to you. In this example there is a model which
> > contains a linked list of lines. The definition of these datatypes looks
> > like this:
> >
> > Line = POINTER TO RECORD
> > next: Line;
> > x0, y0, x1, y1: INTEGER
> > END;
> >
> > Model = POINTER TO RECORD (Models.Model)
> > lines: Line
> > END;
> >
> > And internalize for this model is defined this way:
> >
> > PROCEDURE (m: Model) Internalize (VAR rd: Stores.Reader);
> >
> > For pointer types, "VAR" is not needed in method definitions. It's the
> > contets of the model that will be changed, not the model pointer.
> >
> > If this doesn't help to solve your problem, then maybe you can
> describe your
> > problem more in detail or send us your program.
> >
> > Regards,
> > Bengt, Oberon microsystems inc.
> >
> >
> > > -----Original Message-----
> > > From: Mary Kynn [mailto:m.kynn{([at]})nowhere.xy> > > Sent: Dienstag, 22. August 2000 06:27
> > > To: blackbox{([at]})nowhere.xy> > > Subject: RECORD vs POINTER TO RECORD
> > >
> > >
> > > When I define
> > >
> > > Model = RECORD (Models.Model)
> > > etc
> > >
> > > instead of
> > >
> > > Model = POINTER TO RECORD (Models.Model)
> > > etc
> > >
> > > and then try to define the internalize/externalize etc
> > > PROCEDURE (VAR m: Model) Internalize- (VAR rd: Stores.Reader)X;
> > >
> > > I get the error message (at X) that the parameter doesn't match (there
> > > may be other errors as well in defining the Model this way)
> > >
> > > I have tried to define the model as a record because the
> model contains
> > > linked lists (which I want to alter within methods) and cannot call a
> > > pointer by reference in the receiver of methods.
> > >
> > > Can anyone help me with this?
> > >
> > > regards,
> > > Mary Kynn
> > >
> > > School of Mathematical Sciences
> > > Queensland University of Technology
> > > Australia
> > >
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Received on Fri Aug 25 2000 - 12:52:05 UTC