[Python-Dev] Re: Update PEP 292

[Raymond Hettinger]

> ... the implementation (patch) I'm going to post
> will require throw the ValueError for all bad placeholders.

Since you're overriding the mod operator, it may be best to emulate its
behavior which is to throw a KeyError:



>>> '%(bingo)s' % {'bongo':'xxx'}

Traceback (most recent call last):
  File "<pyshell#1>", line 1, in -toplevel-
    '%(bingo)s' % {'bongo':'xxx'}
KeyError: 'bingo'



Raymond