Can you enumerate an enum?

#1

In this code:

namespace ConsoleApplication6;

interface

   uses 
      System.Collections.Generic;


   type
      myenum = public enum( test1 , test2 ) of integer;


   type
      ConsoleApp = class
         public
            class method Main(args: array of string);
            class x : List<string>;
         end;

implementation

   class method ConsoleApp.Main(args: array of string);
      begin
      // add your own code here
      Console.WriteLine('Hello World.');

      x := new List<String>;
      x.add('test' );
      for each y in x do begin
         Console.WriteLine( y );
         end;

      for each e : integer in myenum do begin
         Console.WriteLine( e.ToString );
         end;
      end;
   end.

I can enumerate the list, but the compiler doesn’t seem to like me enumerating the enum. Is there a syntax that allows that?

#2

Mark,
have you tried Enum.GetNames

#3

Patrick,

Nope, didn’t try anything. I was just trying to find out if Oxygene had the syntax to enumerate an enum. I was reading an article where someone was proposing some code that allowed them to iterate the enum in C# and I was wondering if Oxygene allowed it.

And maybe if Oxygene doesn’t, that might be something to implement.

#4

Hello Mark,

I have logged a feature request (68375: Enumerate an enum feature) for further review.

Best regards.

#5

Is this feature ever implemented? It is very useful.

Thank you

#6

Looks like this was done, yeah. I have an open Docs issue to document it, I’ll try to get to that next week…

#7

Any update? How to enumerate an enum?

#8

I was told it should just work. Can you give me a test case to show exactly what you are trying that doesn’t?

#9

It should just work like what? What is the required syntax?

By trial and error, it seems the folowing works, but is it the correct way?

DeviceType = public enum (CPU, GPU, TPU);
for each el in typeOf(DeviceType).Constants do writeLn(el.Name + ‘:’ + el.Value.ToString);

#10

for i: DeviceType := low(DeviceType) to high(DeviceType) do should do too. (iirc)

#11

I thought we made it so you can just do

for d in DeviceType do

?

#12

That doesn’t seem to work for me on Island/Windows.

Anyway, my goal is to have a generic method to convert a String to enum, and I found the following just works fine, using typeOf(T).Constants:

method AsEnum<T>(const aStr: NotNull<String>): Tuple of (Boolean, nullable T);   
begin
  result := (false, nil);
  if not typeOf(T).IsEnum then exit; 
  for each el in typeOf(T).Constants do begin
    if el.Name.Equals(aStr) then exit (true, T(el.Value));
  end;
end;
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