Re: [Vala] request to add another example to Projects/Vala/ListExample

["Gilzad Hamuni" <gilli4 gmx net>]

Hi Gergely,

Yesterday I noticed that Vala 0.32.1 magically compiled my project with a stable memory consumption.

I was going to say "yes, please do add an example!" but then decided to check if Mohan's use case still 
applies.
So I wrote this:

void main ()
{
        Gee.List<string> list0 = new Gee.ArrayList<string>();
        Gee.List<unowned string> list1 = new Gee.ArrayList<unowned string>();
        
        list0.add("helloworld");
        list1.add("helloworld");
        
        print("list0.length="+list0.size.to_string()+",
                list1.length="+list1.size.to_string()+"\n");
        // output: list0.length=1, list1.length=1

        list0.remove("helloworld");
        list1.remove("helloworld");
        
        print("list0.length="+list0.size.to_string()+",
                list1.length="+list1.size.to_string()+"\n");
        // output: list0.length=0, list1.length=0
}
 
So it seems that Vala does a clean job when removing items from a Gee.List<G> now, no matter whether I use an 
unowned type in the generics or not.

Note that I couldn't exactly resemble Mohan's example. I only get to call a ctor of an implemented type (e.g. 
ArrayList, not List), so my example might prove something different in the end. Just in case it's relevant 
for our discussion.


Best,

gilzad




Gesendet: Mittwoch, 22. Juni 2016 um 11:10 Uhr
Von: "Gergely Polonkai" <gergely polonkai eu>
An: "Gilzad Hamuni" <gilli4 gmx net>
Cc: vala <vala-list gnome org>
Betreff: Re: [Vala] request to add another example to Projects/Vala/ListExample

Hello,
 
this is a pretty old topic, but I have the rights to edit wgo pages. If you think it is actually relevant, I 
can add this example to the wiki.
 
Best,
Gergely
 

 

Gergely 
Polonkai[https://about.me/gergely.polonkai?promo=email_sig&utm_source=email_sig&utm_medium=email_sig&utm_campaign=external_links]

about.me/gergely.polonkai[https://about.me/gergely.polonkai?promo=email_sig&utm_source=email_sig&utm_medium=email_sig&utm_campaign=external_links]
 
2016-03-21 15:21 GMT+01:00 Gilzad Hamuni <gilli4 gmx net[gilli4@gmx.net]>:Hi,

just want to say that this is some precious info that I needed to learn yet.

As a C#-guy I wonder from a "user's" point of view:
If List<string> implies strdup(), wouldn't it be consistent to automatically compare with strcmp() upon 
removing, too?

Or am I making dangerous assumptions that are not so smart in the end? I might be spoiled by too much comfort.

gilzad


> Gesendet: Freitag, 18. März 2016 um 22:33 Uhr
> Von: MohanR

> HI,
> I screwed-up that comment. sorry for that. I tried to upload a new
> version of that page, but wiki says I'm not allowed. Please help to
> update that page.
> int main(string[] args) {
>     List<string> list0 = new List<string>();
>     List<unowned string> list1 = new List<unowned string>();
>     list0.append("helloworld"); /* g_strdup() takes place */
>     list1.append("helloworld"); /* no g_strdup() */
>     stdout.printf("list0.length=%u, list1.length=%u\n",
>                   list0.length(), /* length=1 */
>                   list1.length()); /* length=1 */
>     list0.remove("helloworld"); /* wont work as expected */
>     list1.remove("helloworld"); /* works as expected */
>     stdout.printf("list0.length=%u, list1.length=%u\n",
>                   list0.length(), /* still length=1 */
>                   list1.length()); /* length=0 */
>     list0.delete_link(list0.find_custom("helloworld", strcmp));
>     stdout.printf("list0.length=%u, list1.length=%u\n",
>                   list0.length(), /* length=0 */
>                   list1.length()); /* length=0 */
>     return 0;
> }
> Thanks,
> Mohan R
> On Fri, 2016-03-18 at 20:37 +0100, Luca Bruno wrote:
> > Hi,
> > thanks a lot for your contribution. The wiki is open, you can
> > register and edit it freely! :)
> >
> > Also pay attention to the comment about "how" and "how". In C, they
> > are equivalent because those are const strings and have the same> > address. But with List<string> they 
> > get copied. However with
> > List<unowned string> they would be equal. It would be better if you

> > could reword that comment about pointing to the ownership of the List
> > elements
> >
> > On Fri, Mar 18, 2016 at 8:26 PM, MohanR <mohan43u gmail com[mohan43u@gmail.com]> wrote:
> > > Hi,
> > >
> > > I'm a beginner in vala. I would like to add the following example
> > > to
> > > this wiki link to make other beginners understand important thing
> > > about
> > > List<string>.
> > >
> > > https://wiki.gnome.org/Projects/Vala/ListSample[https://wiki.gnome.org/Projects/Vala/ListSample]
> > >
> > > int main(string[] args) {
> > >     List<string> mylist = new List<string>();
> > >     mylist.append("hi");
> > >     mylist.append("how");
> > >     mylist.append("are");
> > >     mylist.append("you");
> > >
> > >     /* prints length: 4 */
> > >     stdout.printf("length: %u\n", mylist.length());
> > >
> > >     /* following wont work as expected because in
> > >      * C universe, "how" and "how" is not equal
> > >      */
> > >     mylist.remove("how");
> > >
> > >     /* still prints length: 4 */
> > >     stdout.printf("length: %u\n", mylist.length());
> > >
> > >     /* works because "how" and "how" is equal
> > >      * according to strcmp()
> > >      */
> > >     mylist.remove_link(mylist.find_custom("how", strcmp));
> > >
> > >     /* prints length: 3 */
> > >     stdout.printf("length: %u\n", mylist.length());
> > >
> > >     return 0;
> > > }
> > > _______________________________________________
> > > vala-list mailing list
> > > vala-list gnome org[vala-list@gnome.org]
> > > https://mail.gnome.org/mailman/listinfo/vala-list[https://mail.gnome.org/mailman/listinfo/vala-list]
> >
> >
> > -- 
> > NixOS Linux
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