Re: It seems pure ain't so pure after all

[Steven Schveighoffer]

On Mon, 01 Oct 2012 16:23:17 -0400, Tommi <tommitiss...@hotmail.com> wrote:
On Monday, 1 October 2012 at 20:16:09 UTC, Steven Schveighoffer wrote:
We already have that, use templates:

private auto _funimpl(string s) {
/* what was previously in fun(string) */
}

template fun(string s)
{
   enum fun = _funimpl(s);
}

// usage:

fun!("times"); // always executes _funimpl at compile time

Yes, I know. And this helps even more:

template ct(alias expr)
{
      enum ct = expr;
}

auto fun(string s)
{
      ...
}

// usage:

ct!(fun("times"))

But that's still a nuisance.

Hm... I was focusing on changing fun("times") into fun!("times") in order  
to make it always execute at compile time.  I think that is not so bad.

The idea is that _funimpl is implementation details for fun, and doesn't  
ever expect to be called at runtime.  In fact, you could do if(!_ctfe)  
throw Error();

-Steve