" " == Brett Cannon <brett@python.org> writes:
> I just wanted to quickly say that Guido's observation as to how > a VFS is overkill is right. Imagine implementing a loader using > sqlite and you quickly realize that doing a dull VFS is more > than necessary to implement what import needs to function. I fear I've made a poor choice in calling this abstract class a VFS (I'm terrible with names). I'm not thinking of anything along the lines of a full file system that supports open(), seek(), read() and everything else. That for sure would be overkill and way more complicated than it needs to be. All I'm really thinking about is a simple abstract interface that is used by an importer to actually locate and retrieve the binary objects that will be loaded. For the simple case I think just two methods would/could server a read only "blob/byte database": listdir(path) # returns an iterable container of "files"/"dirs" found # at path get(path) # returns a bytes object for the given path I think with those two virtual calls a more high level import layer can locate and retrieve modules to be loaded without even knowing where they came from. The higher level would know about things such as the difference between .py and .pyc "files" or the possible existance of __pycache__ directories and what may be found in them. Right now the zipimporter contains a list of file extensions to try and load (and in what order). It also lacks any knowledge of __pycache__ directories (which is one of the outstanding bugs with it). It just seems to me that this sorta logic would be better moved to a higher layer and the zip layer just translates paths into reads of byte blobs. I mentioned write()/put() for two reasons: 1) When I import a .py file then a .pyc file is created on my filesystem. I don't really know what piece of code created it. But a write to the filesystem (assuming it is writeable and permissions set etc) occurs. It might be nice for other storage systems (zip, sql, etc) could optionally support this. They could if the code that crated the .pyc simply did a put() to the object that pulled in the .py file. The interface is expanded by two calls (put() and delete()). 2) Integration with package data. I know there are modules/packages out there that help a module try and locate data files that may be associated with a package. I think it would be kinda cool for a module to instead be able to get a handle to the abstract class that loaded it. it could then use the same listdir() get() and possibly write methods the importer did. The writing bit of this may or may not be a good idea :) Anyway, hope I did not muddy the waters. I was just thinking a bit out loud and none of this may live past my own experiments. I was/am just trying to think of why the importers like the zipimporter don't work like a filesystem importer and how they would be cleaner if they just dealt with paths and byte blobs to store/get based on those paths. Mike