Re: Possible to fix glaring Gjs API issues before GNOME 4?

["Torsten Schönfeld" <kaffeetisch gmx de>]

Von: "Martin Pitt" <martin pitt ubuntu com>:
> > 1. Some functions return useless "success" boolean: for example
> > [success, contents, etag_out] = GFile.load_contents(). When C
> > g_file_load_contents returns false, it also sets GError, so in Gjs it's
> > either true or the function has thrown exception.
>
> Note that many other functions with that style don't throw a GError.
> In PyGObject we have overrides for many of them to filter out the bool
> and only return the (out) arguments if the return value is True. Look
> for "strip_boolean_result" in
> http://git.gnome.org/browse/pygobject/tree/gi/overrides/Gtk.py

We use a similar approach in the Perl bindings: 
<http://git.gnome.org/browse/perl-Glib-Object-Introspection/tree/lib/Glib/Object/Introspection.pm#n48>, 
<http://git.gnome.org/browse/perl-Gtk3/tree/lib/Gtk3.pm#n49>.

When functions with a "success" boolean and out arguments don't throw an exception, you can still get rid of 
the boolean if your language supports a variable number of return values.  You simply return nothing then in 
the case the boolean is false.

But note that you cannot use a heuristic like "has boolean return value and out arguments" to decide whether 
to apply this approach: gtk_tree_selection_get_selected is a counter example, 
<http://developer.gnome.org/gtk3/3.2/GtkTreeSelection.html#gtk-tree-selection-get-selected>.

I also think an annotation for boolean return values that states "this is a sentinel for whether the out args 
have been set" would be useful.  It would make it possible for bindings to share this information.