use argparse for more consistent and robust argument parsing.

sys.path.append('..')

from install_helpers import error,get_cpus,fullpath,which,geturl

# help message

from argparse import ArgumentParser

parser = ArgumentParser(prog='Install.py',

                        description="LAMMPS library build wrapper script")

# settings

version = "voro++-0.4.6"

url = "http://math.lbl.gov/voro++/download/dir/%s.tar.gz" % version

# extra help message

help = """

Syntax from src dir: make lib-voronoi args="-b"

                 or: python Install.py -b

                 or: python Install.py -p /usr/local/voro++-0.4.6

specify one or more options, order does not matter

  -b = download and build the Voro++ library

  -p = specify folder of existing Voro++ installation

  -v = set version of Voro++ to download and build (default voro++-0.4.6)

Example:

make lib-voronoi args="-b"   # download/build in lib/voronoi/voro++-0.4.6

make lib-voronoi args="-p $HOME/voro++-0.4.6" # use existing Voro++ installation in $HOME/voro++-0.4.6

"""

# settings

version = "voro++-0.4.6"

url = "http://math.lbl.gov/voro++/download/dir/%s.tar.gz" % version

# parse and process arguments

# parse args

pgroup = parser.add_mutually_exclusive_group()

pgroup.add_argument("-b", "--build", action="store_true",

                    help="download and build the Voro++ library")

pgroup.add_argument("-p", "--path",

                    help="specify folder of existing Voro++ installation")

parser.add_argument("-v", "--version", default=version,

                    help="set Voro++ version of Voro++ to download and build (default: %s)" % version)

args = sys.argv[1:]

nargs = len(args)

if nargs == 0: error(help=help)

args = parser.parse_args()

homepath = "."

homedir = version

# print help message and exit, if neither build nor path options are given

if args.build == False and not args.path:

  parser.print_help()

  sys.exit(help)

buildflag = False

pathflag = False

buildflag = args.build

pathflag = args.path != None

voropath = args.path

linkflag = True

iarg = 0

while iarg < nargs:

  if args[iarg] == "-v":

    if iarg+2 > nargs: error(help=help)

    version = args[iarg+1]

    iarg += 2

  elif args[iarg] == "-p":

    if iarg+2 > nargs: error(help=help)

    voropath = fullpath(args[iarg+1])

    pathflag = True

    iarg += 2

  elif args[iarg] == "-b":

    buildflag = True

    iarg += 1

  else: error(help=help)

homepath = fullpath(homepath)

homepath = fullpath(".")

homedir = "%s/%s" % (homepath,version)

if (pathflag):

    if not os.path.isdir(voropath): error("Voro++ path does not exist")

    homedir = voropath

if (buildflag and pathflag):

    error("Cannot use -b and -p flag at the same time")

if (not buildflag and not pathflag):

    error("Have to use either -b or -p flag")

# download and unpack Voro++ tarball

if buildflag:

# create 2 links in lib/voronoi to Voro++ src dir

if linkflag:

print("Creating links to Voro++ include and lib files")

if os.path.isfile("includelink") or os.path.islink("includelink"):

  os.remove("includelink")