[Python-Dev] Re: [Distutils] Questions about distutils strategy

[Gordon McMillan]

James C. Ahlstrom wrote:

> Jean-Claude Wippler wrote:
> 
> > Ouch - what's wrong with zip archives?

> In general Zip archives store whole branches of a file
> system.  

> The archive format stores modules as dotted names, just as they
> appear in the import statement.  The search path is "." in every
> archive file by definition.  The import statement "import foo"
> just results in a dictionary lookup for key "foo", not a search
> through a zip directory along a local search path for
> "foo.something" where "something" can be pyc, pyo, py, etc.
> 
> The intent was to link the archives to the import statement, not
> re-create a directory tree.  It borrowed this feature from the
> archive formats of Greg and Gordon.

As I've stated before, I have 2 archive formats. This may seem 
a needless complication, but my suspicion is that sooner or 
later, people will want 2 different kinds.

One is a .pyz format, which corresponds closely to Jim's .pyl 
format (with a number of minor differences: it's compressed, 
the archive as a whole has the Python magic number, instead 
of each entry, and it's not designed for concatenation).
 
The other is like a zip, and probably should be zip format.  It's 
designed to hold _anything_, and can be manipulated from C 
and from Python. It can be concatenated and / or embedded 
(and the innner one opened without extraction). It's table of 
contents is more file-system like. Importing from one is 
slower, but that's not really what it's for. It's for packaging up 
arbitrary resources. Like .pyz's, or Tcl/Tk for Tkinter apps, or 
configuration files.

Jim is correct that a good importer (which can say "No, it's not 
mine" as quickly as possible) is better satisfied by a simple 
dictionary lookup than fooling with file extensions and 
directories (virtual or real).

> > If you want a marshalled TOC, then why not add a manifest entry
> > for it, sort of like what ranlib does with ar?
> 
> Sorry, I don't understand.  Please explain.

The table of contents is just another entry.
 
> An important feature is the ability to concatenate to a binary:
>   cat python.exe zip1.zip > myapp.exe
> Searching for this isn't fast unless magic numbers are at the
> end.  Are zip files recognizable from the end (I don't know)?

Where do you think we got this idea?

> Are there any zip experts out there?  Can zip files satisfy all
> the design requirements I listed in pylib.html?  Is there zip
> code available?  All my code is in Python.

Hmm. My bookmark appears to be dead (I was there not long 
ago):
http://www.cubic.org/source/archive/fileform/packers/appnote.t
xt

There have been several references on this list to Guido et al 
having some Python / zip code.


- Gordon