Re: -stack-list-locals and children

["André Pönitz" <andre.poenitz@nokia.com>]

On Monday 29 June 2009 10:13:28 Nick Roberts wrote:
>  > > -stack-list-locals doesn't return an numchild element. How can the IDE
>  > > know if a local
>  > > is has children?
>  > > 
>  > > If there are children, they are listed in value:
>  > > ^done,locals=[{name="list",value="QList = {[0] = \"hello\"}"}]
>  > > 
>  > > Is it a good idea to parse the value with an regular expression to
>  > > find out if there are children?
>  > 
>  > It would be really nice if 'type' and 'numchild' information was directly
>  > included in that "primary" output. The information is available on
>  > the gdb side, so parsing it from the 'value' field does not really look
>  > like a good solution in the long run.
> 
> What would you do with this information?

Use it in a GUI frontend to determine whether the item should be
expandable or not. 
 
> Note that -stack-list-locals --simple-values _does_ give type information and,
> if this is presented to the user, he can usually infer the number of children.
> In the manual:
> 
>      -stack-list-locals --simple-values
>      ^done,locals=[{name="A",type="int",value="1"},
>        {name="B",type="int",value="2"},{name="C",type="int [3]"}]
>      (gdb)                                             ^^^^^^^
> 
> C has three children.

Sure I can filter out whatever information is implicitly provided in the output,
and ask for more if needed. But as roundtrips through gdb are expensive
time-wise It would be nicer though if all information necessary to build the
top level of the typical "variable view" could be extracted from gdb in one go.
 
> Remember that these aren't variable objects but in Emacs, at least, you can
> make variable objects from them simply by clicking mouse-2 on them in the
> locals buffer.
> 
> It can be expensive to make variable objects from all the locals every time
> the frame changes but this is what Insight does, and Apple GDB has MI code
> to do it.  So maybe Xcode does too.

Apple creates variables automatically and it is not slow.

Andre'