Implementing a Programming Language in D: Lexical Analysis

[Ali Çehreli via Digitalmars-d-announce]

On 12/28/2015 09:57 PM, Ali Çehreli wrote:

 > anonymous enums

Wow! They are pretty weird:

1) The second form of the AnonymousEnumDeclaration spec is redundant, right?

   http://dlang.org/spec/enum.html#AnonymousEnumDeclaration

     enum : EnumBaseType { EnumMembers }
     enum { EnumMembers }            <-- Redundant?
     enum { AnonymousEnumMembers }

The reason is, AnonymousEnumMembers already covers EnumMembers, no?

2) Anonymous enum definitions can have types right inside the list:

AnonymousEnumMember:
     EnumMember
     Type Identifier = AssignExpression

enum {
     a,
     ulong b = 42, c,   // b and c are ulong
     s = "hello",       // an inferred string between integrals!
     x = 7, y, z
}

3) The types of x, y, and z are 'int' because 7 is an int (they don't 
follow the type of 'c'). However, move 's' to the end of the list or 
remove it altogether, then x, y, and z become ulong! Weird. Ok, I'm 
going to forget about this feature now. :p

Ali