On Thursday, 5 July 2018 at 10:32:01 UTC, Timoses wrote:
int fun(T)(T i)
{
static assert(is(typeof(return) == T)); //true
pragma(msg, is(T == return)); // false
static if (is(T ReturnType == return))
pragma(msg, ReturnType); // does not enter
return i;
}
unittest
{
fun(3);
}
What's the purpose of 'is(T == return)' if not the above?
Found it:
http://ddili.org/ders/d.en/is_expr.html
Section "is (T identifier == Specifier)"
int fun() { return 1337; }
template Temp(T)
{
//pragma(msg, typeof(T));
// is T a function, if so assign its return type to
'retType'
static if (is(T retType == return))
{
retType Temp(T func)
{
return func();
}
}
}
void main()
{
int i = Temp!(typeof(&fun))(&fun);
assert(i == 1337);
}
So, 'return' checks if T is a callable and if so assigns its
return type to 'identifier'.
