D Language Compile Time Function Evaluation (CTFE) Evaluate a function at compile-time
Example
long fib(long n)
{
return n < 2 ? n : fib(n - 1) + fib(n - 2);
}
struct FibStruct(int n) { // Remarks: n is a template
ubyte[fib(n)] data;
}
void main()
{
import std.stdio : writeln;
enum f10 = fib(10); // execute the function at compile-time
pragma(msg, f10); // will print 55 during compile-time
writeln(f10); // print 55 during runtime
pragma(msg, FibStruct!11.sizeof); // The size of the struct is 89
}
