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Date: Sat, 5 Dec 2020 20:18:55 +0000
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Subject: Re: [PHP-DEV] [RFC] Enumerations
From: rowan.collins@gmail.com (Rowan Tommins)

On 05/12/2020 19:21, Marc Bennewitz wrote:
> I mean on mapping something to something else defined as a single assoc array constant.
> Something like:
>
> enum Role {
>    case User,
>    case Admin,
>    ...
> }
>
> enum Action {
>    case Order_Edit,
>    case Order_Read,
>    
>    private const BY_ROLE = [
>      Role::User => [self::Order_Read],
>      Role::Admin => [self::Order_Read, self::Order_Edit],
>    ];
>
>    public function isAllowed(User $user) {
>      return in_array($this, self::BY_ROLE[$user->role]);
>    }
> }


That example can be rewritten directly as a static method and match 
statement, which I think would look like this:

enum Action {
   case Order_Edit;
   case Order_Read;
   
   private static function byRole(Role $role) {
     return match($role) {
        Role::User => [self::Order_Read],
        Role::Admin => [self::Order_Read, self::Order_Edit],
     };
   }

   public function isAllowed(User $user) {
     return in_array($this, self::byRole($user->role));
   }
}


The scenario can also be modelled the other way around with case methods:

enum Action {
   public function isAllowed(User $user) {
      // Default case denying all, might be useful with a long list of cases
      return false;
   }

   case Order_Edit {
      public function isAllowed(User $user) {
         return $user->role === Role::Admin;
      }
   }
   case Order_Read {
      public function isAllowed(User $user) {
         return $user->role === Role::User
                || $user->role === Role::Admin;
      }
   }
}


Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]