[Python-Dev] Another Strategy for Relative Import (original) (raw)

Chris and Ann Reedy chrisandannreedy at comcast.net
Tue Dec 23 15:03:37 EST 2003

Ken Manheimer wrote:

Even using the leading '.' syntax, it would be good to have a specific identifier for the containing package, realized in each module and respected as a special identifier by the package machinery. I like 'pkg': import pkg.sibling # == 'import .sibling' and import pkg.pkg.uncle # == 'import ..uncle' import pkg.pkg.uncle.cousin # == 'import ..uncle.cousin' I think the leading '.' dot forms are a lot nicer, but the presence of a module named 'pkg' would be useful for programmatically mucking navigating the package structure.

Delurking:

Knowing that the statement:

import foo.bar

has the effect of setting the variable foo to reference package foo, even if the variable foo already references something else, I was wondering if it would make sense to changes the semantics of import so that if the variable foo is already assigned and is a package (or maybe a module in some cases), then importing foo.bar would have the effect of importing the module or package bar within foo, using foo.path to search for the module bar and foo.name + '.bar' as the name of the module.

It seems to me that such an approach might be used in a number of cases:

  1. If there is a standard name for the parent of a package, e.g. pkg, then

import__pkg__.bar

just works.

  1. This approach allows the following kind of thing to work:

if : import xyz as util else: import xyz_old as util

import util.bar

  1. This could be used to clean up the problem with os.path. The idea here is that since initialization of os creates the attribute os.path which references a module, then:

import os.path

would have the effect of importing os and then noting that os.path exists and is a module, so no further work is required.

I haven't (yet?) attempted to work out whether this could be used to handle all the use cases for relative import.

Chris

P.S. I've been lurking on this list for a about six months. I just moved between coasts (US) and things are still a mess. I would like to get more involved with Python. I'll send a message in the near future introducing myself.

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