Re: gperl_type_get_property() default on unichar prop

Kevin Ryde wrote:
The program below gets a warning

    Argument "\x{78}" isn't numeric in subroutine entry at line 19.

I think it's because in get_default_property_value() the call out to
Glib::Param::Unichar::get_default_value() gives back a single-char
string 'x' but gperl_value_from_sv() used on that return expects a

Hmm, tricky. The problem seems to be that there is a mismatch between the type of the param spec (G_TYPE_PARAM_UNICHAR) and the GType used to store and marshal values of it (G_TYPE_UINT). When we have the Glib::Param::Unichar object, we know it's a unichar. But when we are dealing with values for properties described by this param spec, we don't have this knowledge and instead only know that we deal with a uint.

I'd be sorely tempted to say Glib::Param::Unichar::get_default_value()
is the odd man out and ought to be returning a number the same as
$obj->get_property or $obj->set_property give and return for a unichar
prop.  But would changing that break anyone's program?

I think Glib::Param::Unichar::get_default_value() doesn't look so odd anymore when you consider that it simply uses the gunichar typemap. Every other xsub that returns or takes a gunichar automatically uses the same one-character string representation.

Changing Glib::Param::Unichar::get_default_value() to return a plain number would break users that directly call it.

The other temptation would be to switch get_default_property_value() to
using g_param_value_set_default(), since that latter does the right
thing on unichar pspecs.  But would anyone have their own subclassed
$pspec->get_default_value() which would be lost by using only
g_param_value_set_default() ?

I don't know. The current get_default_property_value() certainly allows custom param specs to provide their own get_default_value() and have it called when appropriate.

The only possible solution that comes to mind is to attack this at the only place that sees both the GParamSpec and the GValue: get_default_property_value(). Maybe it could, upon a seeing a param spec of type G_TYPE_PARAM_UNICHAR, mangle the SV returned by Glib::Param::Unichar::get_default_value() before passing it to gperl_value_from_sv()?


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]