[OpenWalnut-Dev] WItemSelection & friends improvement

[Sebastian Eichelbaum]

Nice. Thank you. I will have a look at this soon.

Bye
Sebastian

On Tue, 15 May 2012, Christof Pieloth wrote:

> Hello,
> 
> I have created a ticket with the *.diff:
> http://www.openwalnut.org/issues/174
> I decided to extend WItemSelectionItem as a container. This solution
> allows us to use any types even those without a default constructor.
> Sadly we now have a dynamic cast, but due to "downward
> compatibility" we have to take this.
> 
> Bye
> Christof
> 
> 
> Am 14.05.2012 18:28, schrieb Christof Pieloth:
> >Tomorrow I will have a try and can hopefully send you a patch in a
> >few days.
> >
> >Am 14.05.2012 15:56, schrieb 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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> >>>
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> >>>
> >
> 
> -- 
> 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