RE: Object Oriented Inline C

[Ken.Williams]

 

> -----Original Message-----
> From: Sisyphus [mailto:[EMAIL PROTECTED] 
> Sent: Sunday, June 19, 2005 11:06 PM
> To: inline@perl.org
> Subject: Re: Object Oriented Inline C
> 
> 
> In other words,DESTROY() receives as its argument a SV*:
> 
> DESTROY(SV * obj) {// do stuff}
> 
> How does DESTROY() then determine whether it needs to do:
>      Soldier* soldier = (Soldier*)SvIV(SvRV(obj));
> or:
>      Civilian* civilian = (Civilian*)SvIV(SvRV(obj));

You could use the same trick that the perl sources themselves use when
declaring RV, SV, HV, AV, and GV structures: make them share their first
few fields.

            typedef struct {
                int is_soldier;
            } Person;


            typedef struct {
                int is_soldier;
                char* name;
                char* rank;
                long  serial;
            } Soldier;

            typedef struct {
                int is_soldier;
                char* name;
                char* address;
                char* occupation;
                long  age;
            } Civilian;


Then in your code the first thing you can do is:

       Person* p = (Person*)SvIV(SvRV(obj));
       if (p->is_soldier) {
         Soldier* soldier = (Soldier*) p;
         ...
       } else {
         Civilian* civilian = (Civilian*) p;
         ...
       }



I've never actually tried this myself, because it seems like such a bad
design, but it seems like it should work.

 -Ken