[Python-3000] Implementing % formatting in terms of str.format()

[Steven Bethard]

On Sat, Apr 12, 2008 at 8:26 AM,  <skip at pobox.com> wrote:
>
>     Nick> That's exactly the problem though - while a 2to3 fixer can be
>     Nick> written for a tiny subset of formatting calls (those that meet the
>     Nick> constraints you gave)...
>
>  In my personal experience, either the LHS will be a string literal or the
>  RHS will be locals(), globals() or a tuple.  Yes, you will have a hard, if
>  not impossible, time with the general x % y.  Still, I think a fixer that
>  only addresses the "tiny subset" would go a long ways to converting existing
>  code.  For the rest it could insert special comments so the programmer can
>  grep for the problematic cases.

Rather than inserting special comments, why don't we just introduce a
-3 warning for using % string formatting? Then, you can use 2to3 to
convert as much as it can, and you can use the -3 warning to identify
any other places you're using % string formatting and fix them by
hand. Adding such a -3 warning shouldn't be much more than a couple of
lines at the beginning of stringobject.c:PyString_Format.

Steve
-- 
I'm not *in*-sane. Indeed, I am so far *out* of sane that you appear a
tiny blip on the distant coast of sanity.
 --- Bucky Katt, Get Fuzzy