class needs to refer a different class

[ndc85430]

the intention is to provide an instance that is appropriate for the particular file. if an instance of io.IOBase is appropriate, that's what should be returned. but, an instance of this class may be appropriate.

Sounds like a good case for a factory.

[ndc85430]

this is big, so i am not going to post it here. instead, you get a link:
http://ipal.net/python/zopen.py

Yes, there's a lot of code there and it's not too helpful. A really good way to describe in code what you're wanting to do is to write a test. Why? It helps you clarify what you're trying to achieve and to focus on one small part of the problem. "Programming by wishful thinking" is basically what we're doing when we do test-driven development, for those reasons.

Also, when you do want to share your project with people, why provide these individual links, rather than just one link to a repository? That would make it easier for people to get everything and play around with it.

[Skaperen]

here is a script i have made into a command named zhash on my laptop that uses zopen.
http://ipal.net/python/zhash.py
this command hashes each file in an uncompressed form even if it is compressed in the file system as long as the name shows the compression stack. zhash also uses ftrgen (a generator that flattens a file tree).
http://ipal.net/python/ftrgen.py