[Python-Dev] nodef (original) (raw)

Greg Ewing greg.ewing at canterbury.ac.nz
Thu May 24 06:17:55 CEST 2007

Martin Blais wrote:

I don't know what lives in the iterable, so why should I make assumptions?

I think Python needs a builtin for this very purpose. I propose 'nodef', a unique object whose sole purpose is to serve as a default value.

If the aforementioned iterable can yield anything, then it might yield this 'nodef' value as well.

For this reason, there can't exist any standard guaranteed-unambiguous sentinel value. Each use case needs its own, to ensure it's truly unambiguous in the context of that use case.

-- Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | Carpe post meridiem! | Christchurch, New Zealand | (I'm not a morning person.) | greg.ewing at canterbury.ac.nz +--------------------------------------+

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