[Python-Dev] Python install layout and the PATH on win32

Thu Mar 15 00:15:55 CET 2012

On 3/14/2012 5:39 PM, Mark Hammond wrote:
> Can you offer any examples of 3rd party tools which could unify code in
> this scheme, and particularly, where this scheme would cause them to
> have less code, not more?

How about virtualenv:
"""
def path_locations(home_dir):
 """Return the path locations for the environment (where libraries are,
 where scripts go, etc)"""
 # XXX: We'd use distutils.sysconfig.get_python_inc/lib but its
 # prefix arg is broken: http://bugs.python.org/issue3386
 if sys.platform == 'win32':
 [snip a bit about spaces in the path....]
 lib_dir = join(home_dir, 'Lib')
 inc_dir = join(home_dir, 'Include')
 bin_dir = join(home_dir, 'Scripts')
 if is_jython:
 lib_dir = join(home_dir, 'Lib')
 inc_dir = join(home_dir, 'Include')
 bin_dir = join(home_dir, 'bin')
 elif is_pypy:
 lib_dir = home_dir
 inc_dir = join(home_dir, 'include')
 bin_dir = join(home_dir, 'bin')
 elif sys.platform != 'win32':
 lib_dir = join(home_dir, 'lib', py_version)
 inc_dir = join(home_dir, 'include', py_version + abiflags)
 bin_dir = join(home_dir, 'bin')
 return home_dir, lib_dir, inc_dir, bin_dir
"""
> I think you misunderstand the .bat file - there is no python executable
> in the bin directory. The bat file is locating your already installed
> Python and attempting to use it.

My only point here is that it would still find the already-installed 
Python (I think).
> My other questions still remain: who specifically will benefit from
> this, and what would be the cost to those beneficiaries of sticking with
> the existing scheme?

I will benefit, for one. My use case is that I do cross-platform 
development and deployment, and I occasionally want to put an entire 
environment in source control. Currently the case changing and 
Scripts/bin distinction make this a distinct pain, such that I go in and 
edit my Windows python installation in the way that I am describing 
right now.
 From my actual experience with this layout, pip, virtualenv, and pypm 
are the only three major packages that hard-code this logic and would 
need to be changed slightly.
Thanks,
Van