[webkit-dev] Easing printf based debugging in WebKit with an helper.

[Oliver Buchtala]

On 19.07.2012 19:53, Andreas Kling wrote:
> On Tue, Jul 10, 2012 at 4:52 PM, Brady Eidson <beidson at apple.com 
> <mailto:beidson at apple.com>> wrote:
>
>
>     On Jul 10, 2012, at 5:25 AM, Alexis Menard
>     <alexis.menard at openbossa.org <mailto:alexis.menard at openbossa.org>>
>     wrote:
>
>     > On Mon, Jul 9, 2012 at 6:53 PM, Brady Eidson <beidson at apple.com
>     <mailto:beidson at apple.com>> wrote:
>     >>
>     >> On Jul 9, 2012, at 2:43 PM, Alexis Menard
>     <alexis.menard at openbossa.org <mailto:alexis.menard at openbossa.org>>
>     wrote:
>     >>
>     >>> Hi,
>     >>>
>     >>> For those who "secretly" use printf debugging :). I know the
>     >>> recommended way is to use a debugger and it's not the point of
>     this
>     >>> discussion.
>     >>
>     >> A lot of us do this, and sometimes it's necessary.  I agree
>     with the gripe and support adding something easier.
>     >>
>     >>> So I propose wtf() and its stream operator.
>     >>>
>     >>> Usage :
>     >>>
>     >>> wtf()<<"Hello"<<"World"<<3<<4.53322323; will output : Hello
>     World 3 4.53322
>     >>
>     >> There is no reason to bring in stream operators - that are
>     willfully absent from WebCore - just for debugging.
>     >>
>     >
>     > But it's really nice for that purpose, and somehow match std::cout
>
>     And we quite purposefully don't use std::cout in the project.
>
>     >> Overloading functions works just as well.
>     >
>     > I'm not sure to understand what you mean here...
>
>     I mean relying on C++'s overloading of functions for the different
>     types you'd like to printf debug.
>
>     void debug(WebCore::String&);
>     void debug(WebCore::Frame*);
>     void debug(WebCore::Node*);
>
>     etc etc etc.
>
>     debug(someFrame);
>     debug(someNode);
>     debug(someString);
>
>     Especially that last one would help me from remembering how to
>     type "printf("%s", someString.utf8().data())" which is all I've
>     ever really wanted.
>
>
> Hello fellow printfers!
>
> While I'm just as ashamed of my printf habits as the next guy, I think 
> it'd be great if we could move forward with this somehow.
>
> Coming from a background in Qt, the stream operator syntax looks 
> perfectly normal to me, perhaps you could expand on why we want to 
> avoid using these in WebKit. Is there a technical reason, or is it 
> more of a language purity issue?
>
> Regardless, adding a consistent set of debug(WebCore::MyCoolOverload) 
> methods as suggested would still be massively useful.
>
> -Kling
>

Hi,

I am probably one of those people who much dislike printf-debugging.
What is your problem with using a debugger?

Maybe because the displayed information is not appropriate?
E.g., you would like
     someString.utf8().data()
instead of
     someString

FWIW, there is a gdb python API for changing the behavior... so called 
pretty printers.
It is not too difficult to write such pretty-printers.

Maybe providing a set of useful pretty-printers is a better approach 
than providing a set of debug functions?

Regards,
Oliver

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