python implementation replacing "call vsvars32.bat"

setupVSEnv.py

from subprocess import Popen
import os, subprocess

def parseEnv(envoutput):
    handle_line = lambda l: tuple(l.rstrip().split("=", 1))
    pairs = map(handle_line, envoutput)
    valid_pairs = filter(lambda x: len(x) == 2, pairs)
    valid_pairs = [(x[0].upper(), x[1]) for x in valid_pairs]
    return dict(valid_pairs)

def overrideEnv(newenv):
    old = os.environ.copy()
    removed = set(old) - set(newenv)
    for k in newenv.keys():
        os.environ[k] = newenv[k]
    for k in removed:
        os.environ.pop(k)
    return old

def setupVSEnv(vsver):
    si = subprocess.STARTUPINFO()
    si.dwFlags |= subprocess._subprocess.STARTF_USESHOWWINDOW
    cmd = r'cmd /s /c ""%VS{vsver}COMNTOOLS%vsvars32.bat" & set"'.format(**locals())
    ret = Popen(cmd, startupinfo=si, 
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            stdin=subprocess.PIPE)
    output = ret.communicate()[0]
    output = output.split("\r\n")
    old = overrideEnv(parseEnv(output))
    return old

Thanks, this saved me an afternoon

Nice, thanks.

I also refactored it a little bit:

import os
import subprocess as sub


def vs_env_dict(vsver):
    cmd = r'cmd /s /c ""%VS{0}COMNTOOLS%vsvars32.bat" & set"'.format(vsver)
    output = sub.Popen(cmd, stdout=sub.PIPE, stderr=sub.STDOUT, stdin=sub.PIPE).communicate()[0].split("\r\n")

    return dict((e[0].upper(), e[1]) for e in [p.rstrip().split("=", 1) for p in output] if len(e) == 2)

os.environ.update(vs_env_dict(100))