[Python-Dev] pep 362 - 5th edition (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Wed Jun 20 05:24:50 CEST 2012

On Wed, Jun 20, 2012 at 12:36 PM, Yury Selivanov <yselivanov.ml at gmail.com> wrote:

On 2012-06-19, at 9:22 PM, Yury Selivanov wrote:

On 2012-06-19, at 8:39 PM, Nick Coghlan wrote:

7. The idea of immutable Signature objects does highlight an annoyance with the "attribute may be missing" style APIs. To actually duplicate a signature correctly, including its return annotation (and assuming the attribute is renamed), you would have to do something like:

try: note = {"annotation": oldsig.annotation} except AttributeError: note = {} newsig = Signature(oldsig.parameters[1:], **note) BTW, we don't have slices for OrderedDict.  Since the slice object is not hashable, we can implement it safely. I can create an issue (and draft implementation), as I think it'd be quite a useful feature.

No need, my example was just wrong, it should be:

new_sig = Signature(old_sig.parameters.values()[1:])

The constructor accepts an iterable of Parameter objects rather than a mapping.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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