Re: Introspection

[James Henstridge <james jamesh id au>]

Dan Winship wrote:

> On Mon, 2005-01-10 at 12:03 -0500, Matthias Clasen wrote:
>  
>
> > We should probably not cover all irregularities of C apis (varargs come
> > to mind).
> >    
>
> It would be good to at least mention these irregular cases in the
> metadata even if they aren't fully described, so that if you're
> automatically generating bindings, the generator can print out warnings
> telling you that you need to wrap those methods by hand.
>  
If an irregular function was required to use a widget, I'd hope that a 
marshal function could be registered for it in the metadata, providing a 
simpler calling convention.  It would also be nice to have a standard 
"call this function or method" API, that would use a marshaller if 
available, or invoke the function directly otherwise (using libffi or 
something similar).

For many dynamic languages, this would allow bindings to be generated on 
request at runtime, and maybe even allow users to use libraries that 
haven't been wrapped yet.  In essence, the bindings author would just 
have to bind the type system rather than all of GTK ...

> > * type information for parameters and return value
> >    
>
> Lots of methods use "GtkWidget *" as a parameter or return type when the
> actual type required/returned is something more specific. The metadata
> should indicate that.
>  
Is this actually a problem though?  Even if you exclude the cases where 
a more specific return type could have been used, a language binding is 
going to want to pick the most specific wrapper class to represent the 
value.  They could use the same logic here too (also, many functions 
returning GtkWidget* are constructors, which would be handled slightly 
differently anyway).

James.