Re: [slang-users] Can you do OO in Slang?

[Sebastian Gniazdowski <sgniazdowski@xxxxxxxxx>]

Ah, OK, that's fine. But I have to ask: is typecasting of truck onto a car
not possible? I.e.: you cannot typecast() complex types (structs)? It seems
to me that typecast() operates on and returns values, while it should/could
operate on pointers/references if such typecasting of structs would to have
sense. Am I right? I'm asking because I've used to such inheritance
emulation in C, where one has:

typedef struct Button_s {
    Widget base;  /* simulated C++-like inheritance of Widget struct */
    int is_pressed;
} Button;

to then be able to do:

my_base_widget_function ((Widget *)&button);

It would be interesting to do the same in SLang.

On Wed, 27 Jan 2021 at 23:15, John E. Davis <jed@xxxxxxxxxxx> wrote:

> Sebastian Gniazdowski <sgniazdowski@xxxxxxxxx> wrote:
> > in one of the posts that announced a new libslang version I've noticed a
> > syntax that seems to be an inheritance, i.e.:
> >
> >    car = struct { name, price, max_velocity}
> >    truck = struct {@car, max_load};
> >
> > Now truck includes all the fields that car has. I wonder however if you
> can
> > cast a truck at a car, to pass it to a generic car-related function? Is
> > there casting in slang?
>
> Yes, you can pass truck to a routine that expects a car as long as all
> of the fields that the car function needs are present ("duck typing").
> The SLxfig module <https://www.jedsoft.org/fun/slxfig/> makes
> extensive use of this approach.  --John
> _______________________________________________
> For list information, visit <http://jedsoft.org/slang/mailinglists.html>.
>
>

-- 
Sebastian Gniazdowski