Re: [Vala] Upcoming changes in object construction syntax

["Cayle Graumann" <cayle graumann gmail com>]

Jurg,

       I'm having a hard time with the new creation syntax in vapi
files.  As of revision 228, It looks like the compiler is ignoring any
[CCode] directives when it sees a creation method definition .

You can see this with the String.sized method in glib-2.0.vala

Inside of vapi/glib-2.0.vala (line 1197)

        [CCode (cname = "g_string_sized_new")]
       public String.sized (ulong dfl_size);

However when you use this function like so

       var line = new String.sized(1024);

The compiler generates:

       GString* line = g_string_new_sized (1024);

instead of

       GString* line = g_string_sized_new (1024);


Cayle in Missouri.

On 3/3/07, Jürg Billeter <j bitron ch> wrote:
> Hi,
>
> just a heads up that we're about to change some parts of the Vala syntax
> regarding object construction. The new syntax should be more reasoned
> and follow the GObject type system more closely.
>
> It will get a bit harder to follow development of valac in SVN while
> we're adapting the new syntax. We'll release a new version when the
> breaking changes are done.
>
> /**
>  * Example Class to explain the new object construction syntax
>  */
> public class Maman.Bar {
>         /**
>          * Properties
>          * use construct only if the property needs to be set
>          * before the constructor gets executed
>          */
>         public int x { get; set construct; }
>
>         public int y { get; set construct; }
>
>         public string title { get; set; }
>
>         private int x_y;
>
>         /**
>          * Creation Method
>          * corresponds to maman_bar_new in C
>          * runs first
>          * you may only set properties here
>          * properties corresponding to parameters declared with
>          * construct will automatically be set to the argument
>          */
>         public Bar (construct int x, construct int y) {
>         }
>
>         /**
>          * Named Creation Method
>          * corresponds to maman_bar_new_with_title in C
>          */
>         public Bar.with_title (construct string title) {
>         }
>
>         /**
>          * Constructor
>          * runs after the construct properties have been set
>          * often not necessary
>          */
>         construct {
>                 x_y = x + y;
>         }
>
>         static int main (string[] args) {
>                 /* you may set additional properties by name after the
>                  * positional arguments */
>                 var bar = new Bar.with_title ("Hello", x = 10);
>                 return 0;
>         }
> }
>
> Migration of existing code:
>
> * Use new creation method syntax
>         public construct [with_foo] (...) {...}
>                 =>
>         public Bar[.with_foo] (...) {...}
>
> * Ensure that you don't do anything in the body of creation methods
> except setting properties.
>
> * Use new constructor syntax
>         Bar () {...}
>                 =>
>         construct {...}
>
> Regards,
>
> Jürg
>
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