printf() metaprogramming challenge

[Andrei Alexandrescu]

On 5/24/19 7:58 PM, Mike Franklin wrote:
> On Friday, 24 May 2019 at 22:59:10 UTC, Walter Bright wrote:
> 
>> C's printf has been hammered on by literally generations of 
>> programmers over 3 decades. While the interface to it is old-fashioned 
>> and unsafe, the guts of it are rock solid, fast, and correct.
> 
> That may be true, but one problem with `printf` is it is much too large 
> and inefficient for some problem domains [1].
> 
> Rust has a more efficient `printf` alternative which is not dependent on 
> a runtime or libc [2].
> 
> D could offer a *much* more efficient, pay-for-what-you-use 
> implementation that doesn't require libc, a runtime, etc., like Rust's 
> implementation.  It wouldn't be easy (especially wrt floating point 
> types), but it would be a great benefit to D and its users.  Maybe I'll 
> add it to dlang/projects [3].
> 
> There seems to be a perception about C that because it's old and proven, 
> it's magical.  There's nothing `printf` is doing that D can't do better, 
> if someone would just be willing to do the hard work.

The high impact part is the metaprogramming and introspection machinery. 
This is where D can contribute something innovative to the larger 
programming community. Yet another implementation of formatting 
primitives is low impact.