[Python-Dev] PEP 408 -- Standard library __preview__ package

Matt Joiner anacrolix at gmail.com
Fri Jan 27 16:35:53 CET 2012

> A more normal incantation, as is often the way for packages that became
> parts of the standard library after first being a third party library
> (sometimes under a different name, e.g. simplejson -> json):
> try:
>    from __preview__ import thing
> except ImportError:
>    import thing
> So no need to target a very specific version of Python.

I think this is suboptimal, having to guess where modules are located,
you end up with this in every module:

    import cjson as json
except ImportError:
       import simplejson as json
  except ImportError:
      import json as json

Perhaps the versioned import stuff could be implemented (whatever the
syntax may be), in order that something like this can be done instead:

import regex('__preview__')
import regex('3.4')

Where clearly the __preview__ version makes no guarantees about
interface or implementation whatsoever.


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