[Python-3000] More PEP 3101 changes incoming

[Talin]

Ron Adam wrote:
> After a fair amount of experimenting today, I think I've found a nice 
> middle ground that meets some of what both you and Guido are looking 
> for. (And a bit my own preference too.)

First off, thank you very much for taking the time to think about this 
in such detail. There are a lot of good ideas here.

What's missing, however, is a description of how all of this interacts 
with the __format__ hook. The problem we are facing right now is 
sometimes we want to override the __format__ hook and sometimes we 
don't. Right now, the model that we want seems to be:

   1) High precedence type coercion, i.e. 'r', which bypasses __format__.
   2) Check for __format__, and let it interpret the format specifier.
   3) Regular type coercion, i.e. 'd', 'f' and so on.
   4) Regular formatting based on type.

-- Talin