On Wednesday, 28 August 2013 at 23:28:14 UTC, captaindet wrote:
a recent discussion (
http://forum.dlang.org/thread/kvje4r$1tff$1...@digitalmars.com )
about the official enum dox ( http://dlang.org/enum.html ) was
not conclusive whether
enum IDENTIFIER;
is officially allowed/supported. jacob pointed out that it has
an important use case in that it can serve as UDA. as UDAs are
fairly new, this cannot be the reason why this syntax was
allowed in the first place though, *if* it is allowed. also, it
might be used in meta stuff similar to "#define IDENTIFIER" in
C - playing with this idea i run into this issue...
while much code behaves with such an empty enum declaration,
writeln( __traits(compiles, IDENTIFIER) ); // true
writeln( is( IDENTIFIER == enum ) ); // true
typeof() is not happy at all (DMD 2.063.2):
writeln( typeof(IDENTIFIER).stringof );
// Error: argument IDENTIFIER to typeof is not an expression
typeof() expects an expression and a bare identifier is a
"PrimaryExpression" (
http://dlang.org/expression.html#PrimaryExpression ) and hence
a valid argument.
either the empty enum declaration is not allowed (and should be
removed from the dox and throw a compilation error) or there is
a bug in typeof().
/det
typeof only accepts expressions, not types. enum symbol acts as a
type here as it does not have associated value (typeof(int) will
result in same error message)
