std.format expand "%s"

[jmh530 via Digitalmars-d-learn]

I'm playing around with std.format and I'm trying to figure out 
if there is any way to identify what "%s" should expand to.

So for instance:
int x = 1;
auto result = x.format!"%s";

I would know that result="1". I could run "1" through 
unformatValue and get back 1. I'm looking to see if there is a 
way to get back "%d": really a function would be like f(x, "%s") 
produces "%d".

Is there anything like that in std.format?