Extract argument parsing as a separate function

--HG--
branch : distribute
extra : rebase_source : d2143d4dd1332558689b6b90770c013bce3a7e37

distribute_setup.py

@@ -20,6 +20,7 @@ import fnmatch
 import tempfile
 import tarfile
 import optparse
+
 from distutils import log
 
 try:
@@ -496,19 +497,22 @@ def _extractall(self, path=".", members=None):
                 self._dbg(1, "tarfile: %s" % e)
 
 
-def _build_install_args(user_install):
+def _build_install_args(options):
+    """
+    Build the arguments to 'python setup.py install' on the distribute package
+    """
     install_args = []
-    if user_install:
+    if options.user_install:
         if sys.version_info < (2, 6):
             log.warn("--user requires Python 2.6 or later")
             raise SystemExit(1)
-        else:
-            install_args.append('--user')
+        install_args.append('--user')
     return install_args
 
-
-def main(version=DEFAULT_VERSION):
-    """Install or upgrade setuptools and EasyInstall"""
+def _parse_args():
+    """
+    Parse the command line for options
+    """
     parser = optparse.OptionParser()
     parser.add_option(
         '--user', dest='user_install', action='store_true', default=False,
@@ -518,9 +522,14 @@ def main(version=DEFAULT_VERSION):
         default=DEFAULT_URL,
         help='alternative URL from where to download the distribute package')
     options, args = parser.parse_args()
-    tarball = download_setuptools(download_base=options.download_base)
-    _install(tarball, _build_install_args(options.user_install))
+    # positional arguments are ignored
+    return options
 
+def main(version=DEFAULT_VERSION):
+    """Install or upgrade setuptools and EasyInstall"""
+    options = _parse_args()
+    tarball = download_setuptools(download_base=options.download_base)
+    _install(tarball, _build_install_args(options))
 
 if __name__ == '__main__':
     main()