• Lennart Blanco (25/25) Jun 02 2011 Hi
• Nick Sabalausky (9/32) Jun 02 2011 It's a poorly-named hack to allow people to create manifest constants. I...
• Lennart Blanco (6/46) Jun 04 2011 Yes, I understand how anonymous enums works. My question was regarding t...

Lennart Blanco <cokebuttle gmail.com> writes:

Hi

The page for enums specification
http://www.digitalmars.com/d/2.0/enum.htmldefines enum body syntax as
follows:

EnumBody:
;
{ EnumMembers }

Should it not be

EnumBody:
EnumMember ;
{ EnumMembers }

or perhaps

EnumBody:
EnumMembers ;
{ EnumMembers }

Otherwise, I can't quite grasp how following enums definitions are legal:

enum X = 4;

enum
  mega = 1024 * 1024,
  pi = 3.14,
  euler = 2.72,
  greet = "Hello";

(Both of the above enums are accepted by dmd v2.050).

Regards,
Lennart

"Nick Sabalausky" <a a.a> writes:

"Lennart Blanco" <cokebuttle gmail.com> wrote in message 
news:mailman.560.1307076213.14074.digitalmars-d puremagic.com...
 Hi

 The page for enums specification
 http://www.digitalmars.com/d/2.0/enum.htmldefines enum body syntax as
 follows:

 EnumBody:
 ;
 { EnumMembers }

 Should it not be

 EnumBody:
 EnumMember ;
 { EnumMembers }

 or perhaps

 EnumBody:
 EnumMembers ;
 { EnumMembers }

 Otherwise, I can't quite grasp how following enums definitions are legal:

 enum X = 4;

 enum
  mega = 1024 * 1024,
  pi = 3.14,
  euler = 2.72,
  greet = "Hello";

 (Both of the above enums are accepted by dmd v2.050).

It's a poorly-named hack to allow people to create manifest constants. Ie, 
they're like immutable values, but they don't actually take up any space in 
memory. In other words, it works just like C's "#define SOME_VALUE 5": the 
value just gets substituted into the code wherever the name is found.

But keep in mind that means it's not good to use that enum trick for arrays 
and AAs, because then a whole new array or AA will get allocated everywhere 
the enum is actually used.

Lennart Blanco <cokebuttle gmail.com> writes:

On Fri, Jun 3, 2011 at 6:52 AM, Nick Sabalausky <a a.a> wrote:

 "Lennart Blanco" <cokebuttle gmail.com> wrote in message
 news:mailman.560.1307076213.14074.digitalmars-d puremagic.com...
 Hi

 The page for enums specification
 http://www.digitalmars.com/d/2.0/enum.html
defines<http://www.digitalmars.com/d/2.0/enum.htmldefines>enum body syntax as
 follows:

 EnumBody:
 ;
 { EnumMembers }

 Should it not be

 EnumBody:
 EnumMember ;
 { EnumMembers }

 or perhaps

 EnumBody:
 EnumMembers ;
 { EnumMembers }

 Otherwise, I can't quite grasp how following enums definitions are legal:

 enum X = 4;

 enum
  mega = 1024 * 1024,
  pi = 3.14,
  euler = 2.72,
  greet = "Hello";

 (Both of the above enums are accepted by dmd v2.050).

 It's a poorly-named hack to allow people to create manifest constants. Ie,
 they're like immutable values, but they don't actually take up any space in
 memory. In other words, it works just like C's "#define SOME_VALUE 5": the
 value just gets substituted into the code wherever the name is found.

Yes, I understand how anonymous enums works. My question was regarding the D
2.0 specification document. To me it looks like the syntax for anonymous
enums is missing in the specification. Only valid enum body definitions are
empty body or a list of enum members, delimited with '{' abd '}'.

/Lennart