On Monday, October 03, 2016 08:38:22 Jonathan M Davis via Digitalmars-d wrote:
> On Monday, October 03, 2016 23:19:19 Manu via Digitalmars-d wrote:
> > Fill in the blank...
> > I'm having a really hard time with this. I've made it work with a
> > mountain of code, and I want to see what others come up with...
>
> It's certainly possible that this misses something, but it passes all of
> your test cases:
>
> template isStaticMember(T, string member)
> {
> static if(!__traits(hasMember, T, member))
> enum bool isStaticMember = false;
> else
> {
> import std.meta : AliasSeq;
> import std.traits : FunctionTypeOf;
> alias sym = AliasSeq!(__traits(getMember, T, member))[0];
> static if(__traits(isStaticFunction, sym))
> enum bool isStaticMember = true;
> else static if(is(FunctionTypeOf!sym == function) &&
> is(FunctionTypeOf!(typeof(&sym)) == function))
> {
> enum bool isStaticMember = false;
> }
> else
> {
> enum bool isStaticMember = !__traits(compiles, sym.offsetof) &&
> !is(sym == enum) &&
> !is(sym == class) &&
> !is(sym == struct) &&
> __traits(compiles, &sym);
> }
> }
> }
Actually, it can be reduced even further:
template isStaticMember(T, string member)
{
static if (!__traits(hasMember, T, member))
enum bool isStaticMember = false;
else
{
import std.meta : AliasSeq;
import std.traits : FunctionTypeOf;
alias sym = AliasSeq!(__traits(getMember, T, member))[0];
static if (__traits(isStaticFunction, sym))
enum bool isStaticMember = true;
else static if (is(FunctionTypeOf!sym == function) &&
is(FunctionTypeOf!(typeof(&sym)) == function))
{
enum bool isStaticMember = false;
}
else
{
enum bool isStaticMember = !__traits(compiles, sym.offsetof) &&
__traits(compiles, &sym);
}
}
}
Checking for the address makes it unnecessary to check for enums, classes,
or structs.
- Jonathan M Davis
