On Friday, 28 March 2014 at 11:59:47 UTC, Colin Grogan wrote:
I'm interested to hear peoples methods for getting around the
lack of foreach loops while using CTFE?
Currently, I've been using a lot of recursive templates, but
its beginning to give me a headache and I'd like to see if
there's better ways around it.
On a related note, is there plans to add foreach support to
CTFE?
Looks like you mix the terminology here. CTFE is "Compile-Time
Function Evaluation" and means exactly that - interpretation of
normal D function during compile-time. Of course, you can use
foreach as usual inside those.
You post implies that you in fact ask about generic compile-time
algorithms over compile-time argument lists, which is _not_ the
same as CTFE. Indeed, lack of static declarative foreach causes
lot of pain during meta-programming.
Relatively common pattern to avoid recursive template horror is
to use private CTFE function inside the template:
template Stuff(T...)
{
private string doStuff()
{
string result;
foreach (Index, Arg; T)
{
// compute value or generate D code
}
return result;
}
enum Stuff = doStuff();
// ..or for complex code-generating things:
mixin(doStuff());
}
