Re: [Vala] GBinding support?
Hi, On Sun, 2010-06-20 at 17:57 +0200, Frederik wrote: > GLib/GObject 2.26 will add property binding [1]. The straightforward way to > support this in Vala would be: > > Object.bind_property (foo, "x", bar, "y"); > Object.bind_property (foo, "x", bar, "y", BindingFlags.BIDIRECTIONAL); > > However, this is not very type-safe. Would direct language support be > reasonable? E.g. something like > > foo.x +> bar.y; // default > foo.x <+> bar.y;// bidirectional > > Or is it too cryptic? We don't need special syntax for every available GObject method. Let's first have a plain binding and see how it will be used. If we see a very common pattern where syntactic sugar would help a lot, we can reconsider adding syntactic sugar. > And how to deal with 'g_object_bind_property_full'? It takes two > TransformFuncs > but only one user_data/GDestroyNotify pair. This will be fixed, I talked to ebassi on IRC. Jürg ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] GBinding support?
Am 21.06.2010 05:51, Matias De la Puente wrote:
> This stuff is great! very helpful for my project :)
>
> My suggestions:
>
> public class foo : Object
> {
> public int x { set; get; }
> public int y { set; get; }
> }
>
> public class bar : Object
> {
> private Foo foo = new Foo ();
>
> //One possibility
> public int x { set; get; } as foo.x;
> public int y { private set; get; } as foo.y;//one direction
>
> //Another possibility
> public int x { set; get; } bind foo.x;
> public int y { private set; get; } bind foo.y; //one direction
> }
>
> Matias
And what if you want to bind to a property of an object not yet instantiated
at construction time?
Best regards,
Frederik
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Re: [Vala] GBinding support?
Am 21.06.2010 09:29, Fredderic Unpenstein wrote:
> On 21 June 2010 01:57, Frederik wrote:
>> GLib/GObject 2.26 will add property binding [1]. The straightforward way to
>> support this in Vala would be:
>> Object.bind_property (foo, "x", bar, "y");
>> Object.bind_property (foo, "x", bar, "y", BindingFlags.BIDIRECTIONAL);
>
> Would foo.x.bind_property be a possibility? And perhaps
> bind_bidirectional or bind_with (do you bind anything else, other than
> properties, on an object property?)... Maybe then also bind_property
> could become bind_to or something equaly less redundant?
A problem is that 'foo.x' will evaluate to the value of the property,
not representing the property itself. So, if you write
foo.x.bind_property (bar.y);
and if 'foo.x' is 4 and 'bar.y' is 5 it would essentially mean
4.bind_property (5);
> Personaly, I like the operators, but they're a little limited once you
> add extra varients or options, as with the connect family. Unless
> some syntax is added for general operator functions... eg:
>
>foo.x +> [BIDIRECTIONAL] bar.y;
>
> which could also make += signal connection useful again. Perhaps
> adding support for a bracketed comma-separated list with the extra
> arguments, instead.
Personally, I prefer descriptive names over symbolic operators. The question
is whether the property binding feature is essential enough to justify extra
syntax (keyword, operator) just to be type safe.
>> And how to deal with 'g_object_bind_property_full'? It takes two
>> TransformFuncs
>> but only one user_data/GDestroyNotify pair.
>> (foo.x, celsius_to_fahrenheit) <+> (bar.y, fahrenheit_to_celsius);
>> (foo.x, (b, s, t) => { }) <+> (bar.y, (b, s, t) => { });
>
> That's sort of what I was saying with bracketing above, too. A
> general syntax pattern like that might help with other places where
> syntactic support would be useful but presently shunned.
>
>
> Fredderic
>
Best regards,
Frederik
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Re: [Vala] Adding my custom object to libGee.List...
On 06/21/10 11:20, Xavier Bestel wrote: > On Sun, 2010-06-20 at 21:28 +0300, Arkadi Viner wrote: >> Thanks, that did the trick. >> >> On Sun, Jun 20, 2010 at 5:02 AM, Didier 'Ptitjes' wrote: >> >>> Hi, >>> >>> On 06/19/10 23:48, Arkadi Viner wrote: *so, the declaration look like this:* private Gee.List pdfDocuments = new Gee.ArrayList (); *and when I try to add some thing to it:* pdfDocuments.add(new PdfDocument(file_chooser.get_filename >>> ()); *I get compilation error:* main.vala:99.13-99.24: error: missing generic type arguments Process return 256 execution time: 0.90 s >>> >>> I guess you have to make your declaration: >>> >>> private Gee.List pdfDocuments = >>>new Gee.ArrayList (); > > How about: > > var pdfDocuments = new Gee.ArrayList (); I thought "var" only worked for a local variable. Am I wrong ? Here pdfDocuments is a private member. Best regards, Didier. ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] Adding my custom object to libGee.List...
On Sun, 2010-06-20 at 21:28 +0300, Arkadi Viner wrote: > Thanks, that did the trick. > > On Sun, Jun 20, 2010 at 5:02 AM, Didier 'Ptitjes' wrote: > > > Hi, > > > > On 06/19/10 23:48, Arkadi Viner wrote: > > > *so, the declaration look like this:* > > > private Gee.List pdfDocuments = new Gee.ArrayList (); > > > > > > *and when I try to add some thing to it:* > > > pdfDocuments.add(new PdfDocument(file_chooser.get_filename > > ()); > > > *I get compilation error:* > > > main.vala:99.13-99.24: error: missing generic type arguments > > > Process return 256 execution time: 0.90 s > > > > I guess you have to make your declaration: > > > > private Gee.List pdfDocuments = > >new Gee.ArrayList (); How about: var pdfDocuments = new Gee.ArrayList (); Xav ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
[Vala] Adding my custom object to libGee.List...
I personally dislike the 'var' usage because it make the code harder to understand. On Mon, Jun 21, 2010 at 12:20 PM, Xavier Bestel wrote: > On Sun, 2010-06-20 at 21:28 +0300, Arkadi Viner wrote: > > Thanks, that did the trick. > > > > On Sun, Jun 20, 2010 at 5:02 AM, Didier 'Ptitjes' > wrote: > > > > > Hi, > > > > > > On 06/19/10 23:48, Arkadi Viner wrote: > > > > *so, the declaration look like this:* > > > > private Gee.List pdfDocuments = new Gee.ArrayList (); > > > > > > > > *and when I try to add some thing to it:* > > > > pdfDocuments.add(new > PdfDocument(file_chooser.get_filename > > > ()); > > > > *I get compilation error:* > > > > main.vala:99.13-99.24: error: missing generic type arguments > > > > Process return 256 execution time: 0.90 s > > > > > > I guess you have to make your declaration: > > > > > > private Gee.List pdfDocuments = > > >new Gee.ArrayList (); > > How about: > > var pdfDocuments = new Gee.ArrayList (); > >Xav > > ___ vala-list mailing list vala-list@gnome.org http://mail.gnome.org/mailman/listinfo/vala-list
Re: [Vala] GBinding support?
On 21 June 2010 01:57, Frederik wrote:
> GLib/GObject 2.26 will add property binding [1]. The straightforward way to
> support this in Vala would be:
> Object.bind_property (foo, "x", bar, "y");
> Object.bind_property (foo, "x", bar, "y", BindingFlags.BIDIRECTIONAL);
Would foo.x.bind_property be a possibility? And perhaps
bind_bidirectional or bind_with (do you bind anything else, other than
properties, on an object property?)... Maybe then also bind_property
could become bind_to or something equaly less redundant?
Also, is there any way to get rid of the need for BindingFlags in
that? If the argument IS a BindingFlags, Vala could include that
scope when looking up bare words...?
> However, this is not very type-safe. Would direct language support be
> reasonable? E.g. something like
>
> foo.x +> bar.y; // default
> foo.x <+> bar.y; // bidirectional
>
> Or is it too cryptic?
There's also := type notation, which fels like "more than assignment".
Though since binding takes flags, I worry that it'll end up going the
same way as += for signal connection.
Personaly, I like the operators, but they're a little limited once you
add extra varients or options, as with the connect family. Unless
some syntax is added for general operator functions... eg:
foo.x +> [BIDIRECTIONAL] bar.y;
which could also make += signal connection useful again. Perhaps
adding support for a bracketed comma-separated list with the extra
arguments, instead.
> And how to deal with 'g_object_bind_property_full'? It takes two
> TransformFuncs
> but only one user_data/GDestroyNotify pair.
> (foo.x, celsius_to_fahrenheit) <+> (bar.y, fahrenheit_to_celsius);
> (foo.x, (b, s, t) => { }) <+> (bar.y, (b, s, t) => { });
That's sort of what I was saying with bracketing above, too. A
general syntax pattern like that might help with other places where
syntactic support would be useful but presently shunned.
Fredderic
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