On Fri, 06 Apr 2012 09:43:37 -0400, Adam D. Ruppe
<destructiona...@gmail.com> wrote:
On Friday, 6 April 2012 at 13:23:03 UTC, Steven Schveighoffer wrote:
1. Introduce a new compiler-defined attribute @attribute (or @attr or
something better, the name isn't important).
2. This attribute can *only* be used on a module-level function.
This is a fine time to disallow built-in attribute identifiers.
safe is not a keyword:
int safe() { return 0; }
void main() { if(safe) assert(0); }
That's valid code.
But, @safe already has a meaning.
While int safe() is fine, @atttribute int safe() shouldn't
be.
If it throws an error when it sees that declaration, we're
in business.
@attribute int safe()
Error: attribute identifer safe is reserved for the compiler
Good point, I agree.
3. @attribute functions *must* be CTFE-able.
Can this be statically checked? Since CTFE-able-ness
depends on runtime params and errors, I don't think so.
I thought there were two parts to CTFE:
1. The parameters can be determined at compile-time
2. The function has certain attributes (e.g. all source code available,
does not access globals, etc.)
I really was referring to part 2, which I assumed was statically
determined.
This differs from current CTFE-able functions in that the compiler doesn't
know at declaration whether it's going to be used for CTFE or not.
I'd say this should not be a strict requirement on
the declaration. Just let the CTFE fail when you try
to use it.
If this is the only way to do it, I'm fine with that.
-Steve
