[OpenWalnut-Dev] WItemSelection & friends improvement

[Sebastian Eichelbaum]

Hi

This is a nice idea. But technically, there are several things to do to achieve this:

You will need to derive a new templatized class from WItemSelectionItem AND simultanously derive from the template type T. With this, you can use a queried WItemSelectorItem as your own type directly:

template< typename T >
class WIteSelectionItemTyped: public WItemSelectionItem,
                              public T

Luckily, these items are handled using pointers. If they would be handles as copies throughout the WItemSelection, your explicitly derived typing would be lost. Now, you can provide a method to WItemSelectionItem:

const T& getValue() const;
and
T& getValue()
{
  return *dynamic_cast< T* >( this );
}

.. Then you would be able to use the item you query with WItemSelector::at

mySelector->at( someIndex )->getValue< MyType >().MyFunction();

Even nicer would be to also provide WItemSelector::at and atAll with some template type to directly return a pointer to the WItemSelectionItemTyped instance ... awesome :-)

If you implement something like this, we would be very happy to get a patch from you. You can create such a patch via hg export:

$ hg pull -u
$ edit files
$ hg commit -m "[ADD] our nice feature"
$ hg export 


The exported patch can be added by us to the upstream code and next time you do a hg pull, you can merge the stuff in.

Thank you for your idea!
If you have any problems when doing this, just drop a mail to the list!
Sebastian


On Mon, 14 May 2012, Christof Pieloth wrote:

> Hello everybody,
> 
> we are using a "WItemSelection" & friends very often in our project
> and missing a feature.
> In most of our cases we fill a "WItemSelection" with an enum and
> have to code our own mapper to get the corresponding enum value for
> the selected "WItemSelectionItem", which we get from
> "WItemSelector.at()". We may can extend "WItemSelectionItem" to a
> template to hold a value of a generic type and a method like "T
> WItemSelectionItem.getValue()". So you can use a switch-case
> straight away.
> What are you thinking of this idea?
> 
> Best regards
> Christof
> 
> -- 
> HTWK Leipzig, University of Applied Sciences
> Faculty of Electrical Engineering and Information Technology
> Laboratory for Biosignal Processing (LaBP)
> 
> fon:  +49 (0) 341 3076 3133
> fax:  +49 (0) 341 3076 853133
> mail: pieloth 'at' labp.htwk-leipzig.de
> 
> 
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-- 
Dipl.-Inf. Sebastian Eichelbaum
Universität Leipzig
Institut für Informatik
Abteilung Bild- und Signalverarbeitung
PF 100920
D-04009 Leipzig