should we move printf code out of Base?

[StefanKarpinski]

The real motivation is to replace it with something standard that's better in 1.x. The current code works, but it requires macros for invocation, which is suboptimal and has long been (low down) on my todo-list for a redesign. If we make a Printf standard library package then we can evolve this in the future, potentially in a backward incompatible way.

[JeffBezanson]

Yes, that's the spirit! Move out all the things!! :)

I actually don't have a strong opinion on this one though, since printf is such standard functionality.

[StefanKarpinski]

Perusing the code base, @printf is only used in a few utility functions and in parts of Base that should be moved into packages. The laziest future-proof approach to excision is to leave the definition in Base and add a Printf stub module to stdlib that just exports the functionality that's defined in Base. The same approach could be used for other excisions as well.

[StefanKarpinski]

The 1.0 to do here is:

1. unexport @printf and co from Base
2. create Printf in stdlib which exports the above.

Later we can more thoroughly extract this and replace the few uses of printf in Base (mostly to print a fixed number of floating-point digits) with simpler more targeted functionality.