[MAL]
... This means a new PyUnicode_Format() implementation mapping Unicode format objects to Unicode objects.
It's a bitch, isn't it <0.5 wink>? I hope they're paying you a lot for this!
... hmm, there is a problem there: how should the PyUnicode_Format() API deal with '%s' when it sees a Unicode object as argument ?
Anything other than taking the Unicode characters as-is would be incomprehensible. I mean, it's a Unicode format string sucking up Unicode strings -- what else could possibly make *sense*?
E.g. what would you get in these cases:
u = u"%s %s" % (u"abc", "abc")
That u"abc" gets substituted as-is seems screamingly necessary to me. I'm more baffled about what "abc" should do. I didn't understand the t#/s# etc arguments, and how those do or don't relate to what str() does. On the face of it, the idea that a gazillion and one distinct encodings all get lumped into "a string object" without remembering their nature makes about as much sense as if Python were to treat all instances of all user-defined classes as being of a single InstanceType type <wink> -- except in the latter case you at least get a __class__ attribute to find your way home again. As an ignorant user, I would hope that u"%s" % string had enough sense to know what string's encoding is all on its own, and promote it correctly to Unicode by magic.
Perhaps we need a new marker for "insert Unicode object here".
%s means string, and at this level a Unicode object *is* "a string". If this isn't obvious, it's likely because we're too clever about what non-Unicode string objects do in this context.