[Python-Dev] constant/enum type in stdlib (original) (raw)

Michael Foord fuzzyman at voidspace.org.uk
Thu Nov 25 11:34:25 CET 2010

On 25/11/2010 10:12, Nadeem Vawda wrote:

On Thu, Nov 25, 2010 at 11:34 AM, Glenn Linderman<v+python at g.nevcal.com> wrote:

So the following code defines constants with associated names that get put in the repr. The code you gave doesn't work if the constant() function is moved into a separate module from the code that calls it. The globals() function, as I understand it, gives you access to the global namespace of the current module, so the constants end up being defined in the module containing constant(), not the module you're calling it from. You could get around this by passing the globals of the calling module to constant(), but I think it's cleaner to use a class to provide a distinct namespace for the constants.

An idea I had, but have no idea how to implement, is that it might be nice to say:

with importedconstantsfrommodule: dostuff where dostuff could reference the constants without qualifying them by module. Of course, if you knew it was just a module of constants, you could "import * from module" :) But the idea of with is that they'd go away at the end of that scope. I don't think this is possible - the context manager protocol doesn't allow you to modify the namespace of the caller like that. Also, a with statement does not have its own namespace; any names defined inside its body will continue to be visible in the containing scope. Of course, if you want to achieve something similar (at function scope), you could say: def foo(bar, baz): from module import * ...

Not in Python 3 you can't. :-)

That's invalid syntax, import * can only be used at module level. This makes testing import * (i.e. testing your all) annoying - you have to exec('from module import *') instead.

Michael

Python-Dev mailing list Python-Dev at python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/fuzzyman%40voidspace.org.uk

--

http://www.voidspace.org.uk/

READ CAREFULLY. By accepting and reading this email you agree, on behalf of your employer, to release me from all obligations and waivers arising from any and all NON-NEGOTIATED agreements, licenses, terms-of-service, shrinkwrap, clickwrap, browsewrap, confidentiality, non-disclosure, non-compete and acceptable use policies (”BOGUS AGREEMENTS”) that I have entered into with your employer, its partners, licensors, agents and assigns, in perpetuity, without prejudice to my ongoing rights and privileges. You further represent that you have the authority to release me from any BOGUS AGREEMENTS on behalf of your employer.

More information about the Python-Dev mailing list