Re: [Vala] [SimpleType] public struct Integer : uint {} does not work

[Henrik /KaarPoSoft <henrik kaarposoft dk>]

On 01/18/2012 11:27 PM, Jonathan Ryan wrote:
> On Wed, Jan 18, 2012 at 5:20 PM, Jonathan Ryan
> <jryan curious-computing com>wrote:
>
> > On Wed, Jan 18, 2012 at 11:56 AM, Henrik /KaarPoSoft<henrik kaarposoft dk
> > > wrote:
> > > Dear all,
> > >
> > > I am trying to create a new type in vala,
> > > like "typedef" in C.
> > >
> > > http://live.gnome.org/Vala/**Tutorial<http://live.gnome.org/Vala/Tutorial>has this example:
> > > /* defining an alias for a basic type (equivalent to typedef int Integer
> > > in C)*/
> > > [SimpleType]
> > > public struct Integer : uint {}
> > >
> > > However, it does not seem to work...
> > >
> > > I have created the following file called i.vala:
> > > <code>
> > > [SimpleType]
> > > public struct Integer : uint {
> > > }
> > > public static int main (string[] args) {return 0;}
> > > </code>
> > >
> > > Compiling with valac i.vala gives:
> > > /home/henrik/v1/i.c: In function ‘integer_get_type’:
> > > /home/henrik/v1/i.c:22:79: error: ‘integer_dup’ undeclared (first use in
> > > this function)
> > > /home/henrik/v1/i.c:22:79: note: each undeclared identifier is reported
> > > only once for each function it appears in
> > > /home/henrik/v1/i.c:22:109: error: ‘integer_free’ undeclared (first use
> > > in this function)
> > >
> > > This is running on Linux Mint 12 (like Ubuntu Oneiric)
> > > Vala 0.14.0
> > > gcc (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1
> > >
> > > I tried also using latest version of vala from git:
> > > Vala 0.15.0.72-516e7
> > > with the same result.
> > >
> > > valac --save-temps shows only this in i.c:
> > > <snip>
> > > GType integer_get_type (void) {
> > > static volatile gsize integer_type_id__volatile = 0;
> > > if (g_once_init_enter (&integer_type_id__volatile)) {
> > > GType integer_type_id;
> > > integer_type_id = g_boxed_type_register_static ("int32_t",
> > > (GBoxedCopyFunc) integer_dup, (GBoxedFreeFunc) integer_free);
> > > g_once_init_leave (&integer_type_id__volatile, integer_type_id);
> > > }
> > > return integer_type_id__volatile;
> > > }
> > > </snip>
> > > So it is obvious that the C compiler barfs,
> > > integer_dup and integer_free are never defined.
> > >
> > >
> > > Any help on what I am doing wrong here would be most appreciated!
> > >
> > > /Henrik
> > > ______________________________**_________________
> > > vala-list mailing list
> > > vala-list gnome org
> > > http://mail.gnome.org/mailman/**listinfo/vala-list<http://mail.gnome.org/mailman/listinfo/vala-list>
> > Doesn't seem that you're doing anything wrong. Vala isn't generating the
> > normal dup and free functions for your simple type struct. I'm going to
> > check bugzilla if there's a bug about it. This should be removed from the
> > tutorial considering it doesn't work.
> It looks like that deriving from any primitive type is broken. You might be
> able to trick Vala into making it work by defining the functions, but I
> wouldn't do that. My suggestion is to not do this.
Thank you very much for your comments.

If this is broken, I would suggest we try to fix it, instead of just 
removing it from the tutorial!

This allows for nice encapsulation such as this:
<code>
[SimpleType]
public struct PlayingCard {
public int rank() { return this % 13; }
public int suit() { return this / 13; }
public static PlayingCard from_rank_suit(int r, int s) { return s*13+r; } }
public PlayingCard get_card() { return PlayingCard.from_rank_suit(7, 2); }
public void show_suit(PlayingCard c) { stdout.printf("suit=%d\n", 
c.suit()); }
public static int main (string[] args) {
var c=get_card();
show_suit(c);
var clist = new Gee.ArrayList<PlayingCard?>();
clist.add(c);
show_suit(clist.get(0));
PlayingCard[] carr = { c, PlayingCard.from_rank_suit(9, 3) };
show_suit(carr[1]);
return 0;}
</code>

To me, this conveys the intentions behind the code much better than e.g. 
a global
int rank(int card) { return card % 13; }
would.

In valaccodestructmodule.vala we have
add_struct_dup_function (st);
add_struct_free_function (st);
guarded by
if (!st.is_boolean_type () && !st.is_integer_type () && 
!st.is_floating_type ()) {

As far as I can see, this means that a
struct <name>: <boolean/integer/floating_type>
can not be boxed (e.g. for use in a Gee collection).

I have tried to move the dup and free generation outside the guard:
<diff>
diff --git a/codegen/valaccodestructmodule.vala 
b/codegen/valaccodestructmodule.vala
index affb48e..3cae4c9 100644
--- a/codegen/valaccodestructmodule.vala
+++ b/codegen/valaccodestructmodule.vala
@@ -169,9 +169,9 @@ public abstract class Vala.CCodeStructModule : 
CCodeBaseModule {
add_struct_destroy_function (st);
}

- add_struct_dup_function (st);
- add_struct_free_function (st);
}
+ add_struct_dup_function (st);
+ add_struct_free_function (st);

instance_finalize_context = old_instance_finalize_context;

</diff>

Now, if I replace
[SimpleType]
with
[CCode (type_id = "G_TYPE_INT")]
[IntegerType (rank = 6)]
in the card example, it compiles and executes.