[Python-Dev] Very Strange Argument Handling Behavior (original) (raw)

Benjamin Peterson benjamin at python.org
Fri Apr 16 23:51:30 CEST 2010

2010/4/16 Daniel Stutzbach <daniel at stutzbachenterprises.com>:

On Fri, Apr 16, 2010 at 4:11 PM, Raymond Hettinger <raymond.hettinger at gmail.com> wrote:

ISTM that making it illegal costs cycles with giving any real benefit. It is reasonably common to accept **kwds and then pass it down to another function.  Do we want to validate the keys of every kwds dict on every call?  Why do we even care? IIRC, there's a performance hack in dictobject.c that keeps track of whether all of the keys are strings or not.  The hack is designed so that lookup operations can call the string compare/hash functions directly if possible, rather than going through the slower PyObject functions. Consequently, validating **kwds should be cheap.

That won't work. You could put non-string keys in a dictionary and remove them, but the dictionary would still be in the less optimized state.

-- Regards, Benjamin

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