improving debugging experience ;)

[Christian Parpart]

On Friday 09 December 2005 10:49, Vladimir Prus wrote:
> On Friday 09 December 2005 12:36, Christian Parpart wrote:
> > On Friday 09 December 2005 00:46, Andreas Pakulat wrote:
> > > On 08.12.05 22:58:42, Christian Parpart wrote:
> > > > While in debugging mode, you're able to hover a symbol and get it's
> > > > data dump, just like an item in the "Variables View", however,
> > > > it is comprehensivily splitted up into a tree-alike popup stacked
> > > > down to just where your hover the next symbol within this popup.
> > > >
> > > > While this is quite handy, there still is another thing I'm missing.
> > >
> > > Do you mean that this is in kdevelop already? Didn't see it yet, but
> > > maybe just missed it :-)
> >
> > yup, you mixed it up. too bad :-P
> >
> > VS.NET 2005 really has this feature, and once you get in touch with it,
> > it's really very much addictive.
> >
> > do you need screenshots?
>
> Yes, or more detailed description. What you said sounds like the variable
> tooltip has a tree in it, but I have trouble picturing that.

I made a little demo video showing this up (and something else):

http://mylair.de/~trapni/VS2k5DebugDemo-01.avi

FYI: this is captured via VMware movie capture which uses a codec mplayer 
doesn't support on 64bit platforms (yet:(

> > > > So now my idea is that KDevelop would just examine the data structure
> > > > of a variable. If it hits a certain base class FOO containing a
> > > > certain function BAR, then this one gets invoked and its return value
> > > > is used for the pretty display.
> > > > FOO and BAR shall be (of course) configurable, only one BAR per FOO
> > > > and multiple type of FOOs.
> > >
> > > I'm not a debugger expert, but I think this is already done today and
> > > you can do it yourself. For example for QString you get the string
> > > value in the variable view if you include the gdb-macros from the
> > > kdesdk package. I think the same is true for other Qt3 containers, like
> > > QMap and QList, even though I'm currently not sure how they appear in
> > > the variable view.
> > >
> > > If you look at those macros you can see that there's no "magic"
> > > happening, just some "interpretation" of the data in the "d" pointers
> > > of the classes (like QString, QMap and so on).
> > >
> > > > Is this even possible from a kdevelop/gdb technical point of view?
> > >
> > > The question is: Who is skilled enough with gdb to write this for each
> > > and every framework?
> >
> > make it configurable by GDB in form of a listbox containing base class
> > names. each of them can be configured to contain a method to be invoked
> > on display. Think of a list like this:
> >  * [SWL] TObject -> toString().c_str()
> >  * [STL] std::string -> c_str()
> >  * [Qt3] QObject -> toString().however()
> >  * [boost] boostBaseClass -> theirRespectiveToCString()
> >
> > you get the idea on where I'd like to point you?
>
> Yes, this all is reasonable, but we're doing to some limitations in gdb.

> First, it sometimes says local variable exists before its constructor is
> called. So, calling member functions might result in crash.

This is even the case for the other integrated development IDEs such as and 
especially VS.NET 2005.

When you're having a buggy ToString() method, it'll break at the SEGFAULT line 
so that you can debug there. makes sense, eh? :-)

> Second, I don't know how to query gdb if a given type is derived from some
> base type.

traversing down the tree that the KDevelop Variable viewer gives you, you 
really see your base class type names.

That's why I supposed that this is (and I still think so because of this) 
possible.

> I'll try to research this, but if somebody has any ideas, I'm all ears.

thanks.

Regards,
Christian Parpart.
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