Keyed format specifier

[Erik von Reis <evonreis@...>]

My apologies if this is the wrong place to suggest this, but how about 
adding a keyed format specifier for string.format?

To me,

string.format("%(foo)s  = %(bar)d", {foo =  "variable", bar = 22})

which I stole from Python, would be very handy and fits comfortably into 
the primitive way I think about Lua.

Erik von Reis