Hello everyone,

Im new to the D language and have a question regarding a slightly advanced matter:

Im currently porting the code of a game Im writing to D, and right now Im working on the event handling (reacting to user input).
Since Im doing a strategy game, I have several menues and I need a way to connect a menu to the state my game is in, so when the player clicks somewhere, I can use the hashtable to determine which menu class should react.

I think an asossiative array is the way I should go, key would be the state my game is in and the value would be the corresponding Menu.
But since there are several different menu classes, I need some way to put them all in the value area of the array.

In C++, I could make them all inherit from a specific base class, and use the base class as data type for the value, so I effectively had different menues in one datatype in that hashmap.

How can I do this in D?

Moritz <mpipahl@gspgmbh.com> wrote:

> Hello everyone,
>
> Im new to the D language and have a question regarding a slightly advanced matter:
>
> Im currently porting the code of a game Im writing to D, and right now Im working on the event handling (reacting to user input).
> Since Im doing a strategy game, I have several menues and I need a way to connect a menu to the state my game is in, so when the player clicks somewhere, I can use the hashtable to determine which menu class should react.
>
> I think an asossiative array is the way I should go, key would be the state my game is in and the value would be the corresponding Menu.
> But since there are several different menu classes, I need some way to put them all in the value area of the array.
>
> In C++, I could make them all inherit from a specific base class, and use the base class as data type for the value, so I effectively had different menues in one datatype in that hashmap.
>
> How can I do this in D?

The exact same way, for one.


class Menu
{
}

class DerivedMenu : Menu
{
}

Menu[GameState] menuArray;

...

menuArray[currentGameState] = new DerivedMenu();

-- Simen

Moritz wrote:

> Hello everyone,
> 
> Im new to the D language and have a question regarding a slightly advanced matter:
> 
> Im currently porting the code of a game Im writing to D, and right now
> Im working on the event handling (reacting to user input).
> Since Im doing a strategy game, I have several menues and I need a way
> to connect a menu to the state my game is in, so when the player clicks
> somewhere, I can use the hashtable to determine which menu class should
> react.
> 
> I think an asossiative array is the way I should go, key would be the state my game is in and the value would be the corresponding Menu. But since there are several different menu classes, I need some way to put them all in the value area of the array.
> 
> In C++, I could make them all inherit from a specific base class, and use the base class as data type for the value, so I effectively had different menues in one datatype in that hashmap.
> 
> How can I do this in D?

Yes.  Classes can inherit from another class.

class base{}
class menuA : public base{}

D allows only one base class, but many interfaces.

Thanks a lot to both of you :)

Simen Kjaeraas wrote:
> The exact same way, for one.
> 
> 
> class Menu
> {
> }
> 
> class DerivedMenu : Menu
> {
> }
> 
> Menu[GameState] menuArray;
> 
> ...
> 
> menuArray[currentGameState] = new DerivedMenu();
> 
> -- Simen

Jason House wrote:
> Yes.  Classes can inherit from another class.
>
> class base{}
> class menuA : public base{}
>
> D allows only one base class, but many interfaces.