Re: [Oorexx-users] Using Data Class with Attribute to pass data around

[Mark M. <mie...@gm...>]

On Thu, Dec 27, 2012 at 3:50 PM, Art Heimsoth <art...@ar...> wrote:

> I am trying to use a Data Class to pass data between a mother
> and child dialog, where the ::attribute contains a stem variable.
> I have not found how to do this, but if I put a non-stem
> variable in the statements, it seems to work - so I think I have
> the dialogs, methods, class and attribute statements correct.

It will work, although if you are having problems using a stem
variable, I would consider using some other type of object than a
stem.  Use a Directory object in place of a stem.

But, if you are determined to use a stem you probably need to do
something like this:

::class Parent class

::method dataPassingMethod

  data.value1 = 14
  data.value2 = 'Tom'

  obj = .MyClass~new(...)
  obj~data = data.

::class MyClass

::attribute data

::method someMethod

  stm. = self~data
  say 'Name is:' stm.value2
  say 'Number is:' stm.value1

The above will let you use a stem the way you are probably used to
using a stem. Of course you could always use the [] syntax to access
the stem, something like:

::class Parent class

::method dataPassingMethod

  data.value1 = 14
  data.value2 = 'Tom'

  obj = .MyClass~new(...)
  obj~data = data.

::class MyClass

::attribute data

::method someMethod

  name = self~data[value2]
  age = self~data[value1]

Recall that when you use the [] to access the tails, it is case
sensitive.  So I purposefully did not quote the value1 or value2.

> A second part of this is, can I somehow use methods that are
> located in the mother dialog, from the child dialog?

If they are public methods you can.

> I would
> like to keep from replicating several of the common methods
> that are already in use in the mother dialog, from having to
> duplicate the code in the children dialogs.

Using a variation of my above code:

::class Parent class

::method printSecret
  expose secret

  say secret

::method dataPassingMethod

  data. = <set up your data in the stem>

  obj = .MyClass~new(...)
  obj~data = data.
  obj~parent = self

::class MyClass

::attribute data
::attribute  parent

::method someMethod

  stm. = self~data
  self~parent~printSecret




> If so, are the
> exposed variables in the mother dialogs then from the mother
> variable pool or from the child's pool?  Does this make sense?

What you want to do makes sense.  If you have a reference to any
object, you can invoke methods in that object as long as they are
public.  If you make a reference to the parent dialog available to the
child dialog, then the child can invoke any public method in the
parent.

The variable pool part of the question probably indicates a little
confusion on your part.  The exposed variables in the parent dialog
are only available in the parent, and the same thing in the child.
But when you invoke a method in the parent, that method will be
running in the context of the parent, so the method has access to its
exposed variables.  It doesn't have access to any exposed methods in
the child.

--
Mark Miesfeld