Mutually referencing imports -- impossible?
sjmachin at lexicon.net
Mon Jul 14 01:15:47 CEST 2008
On Jul 14, 3:55 am, Matthew Wilson <m... at tplus1.com> wrote:
> I started off with a module that defined a class Vehicle, and then
> subclasses Car and Motorcycle.
> In the Car class, for some bizarre reason, I instantiated a Motorcycle.
> Please pretend that this can't be avoided for now.
> Meanwhile, my Motorcycle class instantiated a Car as well.
> Then I moved the Car and Motorcycle classes into separate files. Each
> imported the Vehicle module.
> Then I discovered that my Car module failed because the global
> Motorcycle wasn't defined. The same problem happened in my Motorcycle
> module. Car and Motorcycle can't both import each other.
And they should not import each other.
> In the beginning, when all three (Vehicle, Car, and Motorcycle) were
> defined in the same file, everything worked fine.
You seem to have a strange notion of "worked fine".
> I don't know how to split them out in separate files now though and I
> really wish I could because the single file is enormous.
What is making a file with 3 classes "enormous"?? What is "enormous"?
> Any ideas?
Your structure is not only bizarre, it is also (sticking with only 1
letter of the alphabet) a Byzantine, baroque, and broken concept.
Asking us to "pretend that this can't be avoided for now" is asking
us to aid and abet you in creating a meaningless and unmaintainable
monster. Consider adding Truck and Bus subclasses. Will each subclass
instantiate the other 3??? You should be able to add or remove a
subclass without having to modify all other subclasses.
The only rational solution is not to have the subclasses refer to each
other. Tell us *why* you think you need to have Car refer to
Motorcycle and vice versa, and we should be able to help you find a
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