Compile time executable calling?

[Tofu Ninja]

So I had an idea recently, wouldn't it be cool to have the 
ability to call an executable at compile time and capture its 
output. Something like the string imports but instead of opening 
and reading a text file, it run an executable, waits for it to 
finish, and grabs its output.

It would get really cool if you could pass this executable some 
args and then mix in its out put into your own code. It could be 
used similarly to how CTFE are used but with out the overhead of 
trying to compile that function and what not and with out the 
limitations on what it can do.

I could imagine all sorts of things that would be possible with 
this that is currently not.

Not sure if this is something that could be implemented easily, 
but seems like something that could be done and something that 
would be really cool.