On Friday, 1 August 2014 at 12:08:23 UTC, John Colvin wrote:
On Friday, 1 August 2014 at 11:55:02 UTC, Tudor Berariu wrote:
On Friday, 1 August 2014 at 10:34:02 UTC, Rene Zwanenburg
wrote:
On Friday, 1 August 2014 at 10:25:39 UTC, Tudor Berariu wrote:
Is it possible to compare at compile time an element from a
TypeTuple with another type?
This code fails:
alias T = Tuple!(int, bool);
static assert(is(T[0] == int));
Error: static assert (is(Tuple!(int, bool)[0] == int)) is
false
Tudor
Tuple is not a type tuple, it's a runtime tuple. TypeTuple is
located in std.typetuple. Use that and your code will work.
Thank you! That works indeed, but my problem is actually a bit
different.
I called that a "TypeTuple" because I read this line in the
documentation "If a tuple's elements are solely types, it is
called a TypeTuple" (http://dlang.org/tuple.html).
What I want to achieve is something like this:
template isNeededType(T) {
enum bool isNeededType = is(T[0] == int);
}
...
enum auto t = Tuple!(int, bool)(3, false);
alias T = typeof(t);
static assert(isNeededType!T);
I know that "is(typeof(t[0]) == int)" works for the above
example, but I need to get, if possible, the types of the
elements from the type of that tuple only.
template isNeededType(T)
{
enum isNeededType = is(T[0] == int);
}
enum t = tuple(3, false);
alias T = typeof(t.expand);
static assert(isNeededType!T);
sorry, that should be
template isNeededType(T ...)
also, please use http://forum.dlang.org/group/digitalmars.D.learn
for these sort of questions
