Vala does support passing a "context" argument, calling user_data to callbacks,
by this two methods(source: FAQ and Tutorial):
1. Passing "this"/self as user_data, for instance method.
2. Variables outside the lambda expression.
Method 2 is done perfectly by Vala, when we talk about lambda expression.
But method 1 is not enough... Not always it's "this"/self what that needed to be
passed.
By now, two ways to overcome this, without using lambda:
* The dirty trick:
instance.event_name.connect (((instance_type*)user_data)->method);
...
private void method ([args]) {
user_data_type* user_data = this;
// Perform action with user_data.
}
* Back to basic(using GLib.Signal namespace):
Signal.connect (instance, "event_name", (GLib.Callback)method, user_data);
...
private static void static_on_stop_clicked ([args], user_data_type user_data) {
// Perform action with user_data.
}
Both works, but I think a proper syntax should be.
I really like the instance.method way for passing callbacks, but it's valid
only for
"this"/self. So, perhaps, instance:method for static methods?
What do you think? Shell Vala support this feature?
Tal
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