Idea: Introduce zero-terminated string specifier

[Jonathan M Davis]

On Tuesday, October 02, 2012 18:21:30 H. S. Teoh wrote:
> On Wed, Oct 03, 2012 at 03:07:14AM +0200, Andrej Mitrovic wrote:
> > On 10/3/12, Jakob Ovrum <jakobovrum at gmail.com> wrote:
> > > writefln cannot be @safe if it has to support an unsafe format
> > > specifier. It's "hidden" because it affects every call to writefln,
> > > even if it doesn't use the unsafe format specifier.
> 
> [...]
> 
> Hmm, this seems to impose unnecessary limitations on @safe. I guess the
> current language doesn't allow for a "conditionally-safe" tag where
> something can be implicitly marked @safe if it's provable at
> compile-time that it's safe?

The format string is a runtime argument, so nothing can be proven about it at 
compile time.

If you want any kind of @safe inferrence, you need to use a template. If 
writefln took the format string as a template argument and generated different 
code (which was @safe or not depending on what it did) based on what was in 
the format string, then inferrence could take place, but otherwise no.

- Jonathan M Davis