Lars T. Kyllingstad wrote:
How can one, in D2, at compile time, convert an integer value (or any
other type, for that matter) to a string? Here's a simplified example of
what I want to do:
import std.conv;
template Say(int N)
{
pragma(msg, to!string(N));
}
mixin Say!(123);
This doesn't compile, because the to!string() function for some reason
can't be evaluated at compile time. (I've included the error messages
below.)
In D1 I used to write N.stringof, which worked as expected, but in D2
this would just print "N" instead of "123".
-Lars
Compile errors:
/usr/local/include/d/druntime/core/memory.di(162): Error: cannot
evaluate gc_malloc(sz,ba) at compile time
/usr/local/include/d/phobos2/std/conv.d(2402): Error: cannot evaluate
malloc(12u,2u) at compile time
/usr/local/include/d/phobos2/std/conv.d(2454): Error: cannot evaluate
to(cast(uint)value) at compile time
tmp.d(5): Error: cannot evaluate to(123) at compile time
tmp.d(5): Error: pragma msg string expected for message, not 'to(123)'
tmp.d(8): Error: mixin tmp.Say!(123) error instantiating
public template Digit(uint n)
{
public static const char[] Digit = "0123456789"[n .. n+1];
}
public template Itoa(uint n)
{
static if(n < 0)
public static const char[] Itoa = "-" ~ Itoa!(-n);
else static if (n < 10)
public static const char[] Itoa = Digit!(n);
else
public static const char[] Itoa = Itoa!(n / 10) ~ Digit!(n %
10);
}
template Say(int N)
{
pragma(msg, Itoa!(N));
}
In D2, replace "const" with "enum" in those declarations if you don't
want storage allocated for the intermediate results.
