• Andrey (4/22) Apr 21 2019 Result:
• Adam D. Ruppe (20/22) Apr 21 2019 You don't. enums don't inherit, but rather have a base type. That
• Alex (11/33) Apr 21 2019 I don't know why you want to do this, just use string directly.

Andrey <saasecondbox yandex.ru> writes:

Hello,
I have got 2 enums. How to inherit one enum from another?
 enum Key : string
 {
     K1 = "qwerty",
     K2 = "asdfgh"
 }
 
 enum ExtendedKey : Key
 {
     E1 = "q1",
     E2 = "w2",
     E3 = "e3"
 }

Result:
 onlineapp.d(27): Error: cannot implicitly convert expression 
 "q1" of type string to Key
 onlineapp.d(28): Error: cannot implicitly convert expression 
 "w2" of type string to Key
 onlineapp.d(29): Error: cannot implicitly convert expression 
 "e3" of type string to Key

How to understand this?

Adam D. Ruppe <destructionator gmail.com> writes:

On Sunday, 21 April 2019 at 20:58:19 UTC, Andrey wrote:
 I have got 2 enums. How to inherit one enum from another?

You don't. enums don't inherit, but rather have a base type. That 
means each enum member must match that base type and the compiler 
is looser about conversions between them, but they do not inherit 
members.

enum Key { // no base type
    K1,
    K2
}

int a = Key.K1; // not allowed

enum Key : int { // base type if int
    K1 = 0,
    K2 = 1,
}

int a = Key.K1; // allowed, because of same base type


 enum ExtendedKey : Key


So this would be defining an enum with base type of Key... 
meaning each member of it must be of type Key. But Key's members 
are NOT carried over.


As far as I know, the language does not permit what you want. 
You'll have to copy over any matching members yourself.

Alex <AJ gmail.com> writes:

On Sunday, 21 April 2019 at 20:58:19 UTC, Andrey wrote:
 Hello,
 I have got 2 enums. How to inherit one enum from another?
 enum Key : string
 {
     K1 = "qwerty",
     K2 = "asdfgh"
 }
 
 enum ExtendedKey : Key
 {
     E1 = "q1",
     E2 = "w2",
     E3 = "e3"
 }

 Result:
 onlineapp.d(27): Error: cannot implicitly convert expression 
 "q1" of type string to Key
 onlineapp.d(28): Error: cannot implicitly convert expression 
 "w2" of type string to Key
 onlineapp.d(29): Error: cannot implicitly convert expression 
 "e3" of type string to Key

 How to understand this?

I don't know why you want to do this, just use string directly.


enum ExtendedKey : typeof(EnumMembers!Key[0])
{
     q = EnumMembers!Key[0]
}


would work..

Alternatively look at this thread:

https://forum.dlang.org/thread/irvtrixunermburvviib forum.dlang.org?page=2

Where you can use the code and classes to subtype and emulate 
enums.