[SOLVED] [Vala] Interfaces not working?

[pikkio]

Hi! I'm new to Vala (http://www.vala-project.org) programming, and actually I'm reading the tutorial right now.

I'll go right to the point: I can't get Interfaces working. Bear in mind that I'm quite comfortable with the Java programming, so it's not a matter of understanding the OOP principles behind interfaces.

Despite that, I can't get compiled even this example code from the tutorial!


using GLib;

public interface ITest {
public abstract int data_1 { get; set; }
public abstract void function_1();
}

public class Test1 : ITest {
public int data_1 { get; set; }
public void function_1() {
}
}

public class Test : Object {

public static void main(string[] args) {
Test1 t = new Test1();
t.function_1();

ITest i = t;
i.function_1();
}
}

These are the two errors I got:


pikkio:vala % valac -o interfaces interfaces.vala
interfaces2.vala:22.13-22.13: error: missing class prerequisite for interface `ITest'
ITest i = t;
^
interfaces2.vala:22.3-22.7: error: missing class prerequisite for interface `ITest'
ITest i = t;
^^^^^
Compilation failed: 2 error(s), 0 warning(s)


Thanks in advance for any suggestion.

P.S. On my Hardy installation I've got the 0.3.5 version of Vala libs

[Quikee]

Looks like you have hit this (http://bugzilla.gnome.org/show_bug.cgi?id=547362). Mind that Vala is still not in a stable state.

[pikkio]

@Quikee: Thanks, I'll post a comment on that bug. Anyway, I'm perfectly aware of Vala's beta state, and it's still doing a damn awesome job at version 0.3.5 :-)

Besides of that, I can't figure out why an official example code doesn't even compile :confused:

[Quikee]

Besides of that, I can't figure out why an official example code doesn't even compile :confused:

Which example? This is possible because examples aren't checked regularly.

[pikkio]

The example I posted before is adapted from the Vala tutorial: http://live.gnome.org/Vala/Tutorial#head-550883e2f1aeebc10f4d160561df2907ff79255c
I've basically done a copy-n-paste, adding the Test class with the main() entry point.

That tutorial is a draft, of course, but in this case it's just showing the basic interfaces syntax...

[pikkio]

Ok, I got it.
A dev on the gnome Bugzilla said it's necessary to put a class (e.g. GLib.Object) as the prerequisite for every interface definition. So the previous example turns to:


using GLib;

public interface ITest : Object {
public abstract int data_1 { get; set; }
public abstract void function_1();
}

public class Test1 : Object, ITest {
public int data_1 { get; set; }
public void function_1() {
}
}

public class Test : Object {

public static void main(string[] args) {
Test1 t = new Test1();
t.function_1();

ITest i = t;
i.function_1();
}
}

I'll mark this topic as Resolved, and I'll file a bug against Vala tutorial, as this behaviour is not documented at all.

Thanks for your attention, anyway :)

[bruce89]

By the way, the "using GLib;" statement is depreciated. GLib is always included now.

[pikkio]

By the way, the "using GLib;" statement is depreciated. GLib is always included now.

Really? It has to be a recent thing, since I've heard about this nowhere...:confused:
So, how it is the way now? I simply omit the "using GLib;" and leave everything else the same, or what?

thanks.

[pikkio]

GLib is always included now.

Mh. I suppose the answer to my question is "Yes" :D

[bruce89]

Really? It has to be a recent thing, since I've heard about this nowhere...:confused:

It was in 0.3.4.


Mh. I suppose the answer to my question is "Yes" :D

Yes, it is yes.