Why does an assignation to 'this' doesn't work?

class A {
    int a;
    void assign(A tmp) { this=tmp; }   //This line
}
void main() {
    A a1= new A(),a2=new A();
    a1.a=4;
    a2.a=5;
    a1.assign(a2);
    printf('%d %d'\n,a1.a,a2.a);
}

Instead of "5 5", it outputs "4 5". I know you might find this weird, but I'd like to know the reasoning behind it.

-------------------------
Carlos Santander


---
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"Carlos Santander B." <carlos8294@msn.com> wrote in news:bed76p$1lsp$1 @digitaldaemon.com:

> Why does an assignation to 'this' doesn't work?
> 
> class A {
>     int a;
>     void assign(A tmp) { this=tmp; }   //This line
> }
> void main() {
>     A a1= new A(),a2=new A();
>     a1.a=4;
>     a2.a=5;
>     a1.assign(a2);
>     printf('%d %d'\n,a1.a,a2.a);
> }
> 
> Instead of "5 5", it outputs "4 5". I know you might find this weird,
but
> I'd like to know the reasoning behind it.

Try this.

     void assign(inout A tmp) { this=tmp; }   //This line

> 
> -------------------------
> Carlos Santander
> 
> 
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.497 / Virus Database: 296 - Release Date: 2003-07-04
> 
> 
> 

"Patrick Down" <pat@codemoon.com> escribió en el mensaje
news:Xns93B1D6772AD29patcodemooncom@63.105.9.61...
| "Carlos Santander B." <carlos8294@msn.com> wrote in news:bed76p$1lsp$1
| @digitaldaemon.com:
|
| > Why does an assignation to 'this' doesn't work?
| >
|
| Try this.
|
|      void assign(inout A tmp) { this=tmp; }   //This line
|

Same result.

————————————————————————— Carlos Santander


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.497 / Virus Database: 296 - Release Date: 2003-07-04

"Carlos Santander B." <carlos8294@msn.com> wrote in news:bedbq5$1qb1$1 @digitaldaemon.com:

> "Patrick Down" <pat@codemoon.com> escribió en el mensaje news:Xns93B1D6772AD29patcodemooncom@63.105.9.61...
>| "Carlos Santander B." <carlos8294@msn.com> wrote in news:bed76p$1lsp$1
>| @digitaldaemon.com:
>|
>| > Why does an assignation to 'this' doesn't work?
>| >
>|
>| Try this.
>|
>|      void assign(inout A tmp) { this=tmp; }   //This line

Actually that was stupid of me.  The issue is that you are not
changing the object that a1 is pointing to.  "this" is like
a local parameter to a functionchangeing it only chages it
for the scope of the functions.

"Patrick Down" <pat@codemoon.com> a écrit dans le message news: Xns93B1E340F1A6Cpatcodemooncom@63.105.9.61...

> Actually that was stupid of me.  The issue is that you are not
> changing the object that a1 is pointing to.  "this" is like
> a local parameter to a functionchangeing it only chages it
> for the scope of the functions.

"this" must be kind of "read only" and produce error on assignement, like ".size" property of object.

-- Nicolas Repiquet