On Saturday, 6 January 2018 at 21:35:19 UTC, user1205 wrote:
On Saturday, 6 January 2018 at 19:35:33 UTC, paul wrote:
Hi!
How to concatenate a tuple of strings at compile time?
[...]
Hello, this simple template does the job:
```
template staticCat(T...)
if (T.length)
{
static if (T.length == 1)
enum staticCat = T[0];
else static if (T.length == 2)
alias staticCat = staticCat!(T[0] ~ T[1]);
else static if (T.length > 2)
alias staticCat = staticCat!(T[0] ~ T[1], T[2..$]);
}
enum elems1 = tuple("foo", "bar");
enum elems2 = tuple("0", "1", "2");
enum elems3 = tuple("a");
```
pragma(msg, staticCat!(elems1.expand));
pragma(msg, staticCat!(elems2.expand));
pragma(msg, staticCat!(elems3.expand));
There might be other solutions, maybe even in std.meta.
There is also this one, less verbose, more efficient (not
recursive template instances):
```
template staticCat(T...)
if (T.length)
{
import std.array;
enum staticCat = [T].join();
}
enum elems1 = tuple("foo", "bar");
enum elems2 = tuple("0", "1", "2");
enum elems3 = tuple("a");
pragma(msg, staticCat!(elems1.expand));
pragma(msg, staticCat!(elems2.expand));
pragma(msg, staticCat!(elems3.expand));
```
