Re: [Vala] Wrapping Errors with g_prefix_error?

[Yu Feng <rainwoodman gmail com>]

On Sat, 2009-08-22 at 09:24 +0200, Jan Hudec wrote:
> On Thu, Aug 20, 2009 at 22:09:21 -0400, Yu Feng wrote:
> > GError doesn't support error wrapping as Java does. Is GLib is purposely
> > avoiding it?
> > If not, it will become a useful feature as the number of libraries that
> > uses GError grows, as the feature has already been proved useful in
> > Java, (indicated in this article):
> > 
> > http://tutorials.jenkov.com/java-exception-handling/exception-wrapping.html 
> 
> Actually, in my opinion that article nicely explains, why you do *not* need
> to have the original error information there.
> 
> article> The main reason one would use exception wrapping is to prevent the
> article> code further up the call stack from having to know about every
> article> possible exception in the system.
> 
> Well, so the code further up the call stack is not going to look at the
> inner exception anyway except to print it to the operator, right? But for
> that, it's enough to embed the wrapped error's message into the wrapping
> error message. The error code is not relevant.
> 
I buy your point. 

In an language like Java, the error(Exception) carries more than a
message and a code. It also includes a source code reference therefore
it make sense to save the cause as an data member.

Nevertheless in the GObject case, because the error only carries an
code, and a message, there is no need to wrap the low level errors.
g_prefix_error would be sufficient as an substitute of 'wrapping'. How
can we invoke this function in vala though?

> By the way, you should be suggesting things like this on the Gtk list, not
> here.

I thought it was a GObject feature which was highly relevant to Vala.


Yu
>