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Vala interface madness
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:date: 2016-02-26T13:07:52Z
:category: blog
:tags: vala,development
:url: 2016/02/26/vala-interface-madness/
:save_as: 2016/02/26/vala-interface-madness/index.html
:status: published
:author: "Gergely Polonkai"
Although I have just started making it in C, I decided to move my Matrix GLib SDK to Vala. First
to learn a new language, and second because it is much easier to write GObject based stuff with
it.
For the first step I created a ``.vapi`` file from my existing sources, so the whole SDK prototype
was available for me in Vala.
I had a ``MatrixEvent`` class that implemented the ``GInitable`` interface, and many others were
subclassed ``MatrixEvent``. For some reason I dont remember, I created the following header for
one of the event classes:
.. code-block:: vala
public class MatrixPresenceEvent : GLib.Object, GLib.Initable {
This is nice and everything, but as I didnt create an ``init()`` method for
``MatrixPresenceEvent``, it tried to use the one from the parent class and somehow got into an
infinite loop. The Vala transformer (``valac``), however, doesnt mention this.
Lessons learned: if you implement an interface on a subclass that is implemented by the parent
dont forget to add the necessary functions to the subclass.