def process_cmd_line(app, opts, args):
    """ Processes the passed command line arguments.

    Input Arguments:
      app -- A Mayavi application instance.

      opts -- The list of options returned by getopt.

      args -- The remaining arguments returned by getopt.
    """

    from mayavi.core.common import error, exception
    from tvtk.common import camel2enthought

    sources = _get_non_file_sources()
    script = app.script
    last_obj = None

    # Start a new scene by default if there is none currently and none
    # was specified at the start of the command line arguments.
    if script.engine.current_scene is None:
        new_scene = False
        if len(opts) == 0:
            if len(args) == 0:
                new_scene = True
        elif (opts[0][0] not in ('-n', '--new-scene', '-z',
                                 '--visualization', '--viz',
                                 '-x', '--exec')):
            new_scene = True
        if new_scene:
            last_obj = script.new_scene()

    for o, a in opts:
        if o in ('-d', '--data'):
            base, ext = splitext(a)
            if exists(a):
                last_obj = script.open(a)
            elif a in sources:
                md = sources[a]
                src = md.get_callable()()
                script.add_source(src)
                last_obj = src
            else:
                error("File/Source %s does not exist!"%a)
                return

        if o in ('-m', '--module'):
            if '.' in a:
                idx = a.rfind('.')
                modname = a[:idx]
                classname = a[idx+1:]
            else:
                modname = 'mayavi.modules.%s'%camel2enthought(a)
                classname = a
            try:
                mod = __import__(modname, globals(), locals(), [classname])
            except ImportError as msg:
                exception(str(msg))
                return
            else:
                m = getattr(mod, classname)()
                if classname == 'Labels':
                    m.object = script.engine.current_object
                script.add_module(m)
                last_obj = m

        if o in ('-f', '--filter'):
            if '.' in a:
                idx = a.rfind('.')
                modname = a[:idx]
                classname = a[idx+1:]
            else:
                if a[:12] == 'UserDefined:':
                    modname = 'mayavi.filters.user_defined'
                    classname = 'UserDefined'
                    # Create the wrapped filter.
                    fname = a[12:]
                    from tvtk.api import tvtk
                    try:
                        extra = getattr(tvtk, fname)()
                    except (AttributeError, TypeError):
                        # Don't worry about errors.
                        extra = None
                else:
                    modname = 'mayavi.filters.%s'%camel2enthought(a)
                    classname = a
                    extra = None
            try:
                mod = __import__(modname, globals(), locals(), [classname])
            except __HOLE__ as msg:
                exception(str(msg))
                return
            else:
                klass = getattr(mod, classname)
                if classname != 'UserDefined':
                    f = klass()
                else:
                    if extra is not None:
                        f = klass(filter=extra)
                    else:
                        f = klass()
                    f.setup_filter()
                script.add_filter(f)
                last_obj = f

        if o in ('-M', '--module-mgr'):
            from mayavi.core.module_manager \
                 import ModuleManager
            mm = ModuleManager()
            script.add_filter(mm)
            last_obj = mm

        if o in ('-n', '--new-scene'):
            script.new_scene()
            e = script.engine
            s = e.scenes[-1]
            e.set(current_scene=s, current_object=s)
            last_obj = s

        if o in ('-x', '--exec' ):
            err = run_script(script, a)
            if err: # stop processing options.
                return

        if o in ('-s', '--set'):
            try:
                stmt = 'last_obj.' + a
                exec(stmt, locals(), globals())
            except Exception as msg:
                exception(str(msg))

        if o in ('-z', '--visualization', '--viz'):
            script.load_visualization(a)

    # for remaining arguments simply load saved visualizations.
    for arg in args:
        base, ext = splitext (arg)
        if ext == '.mv2':
            script.load_visualization(arg)
        elif ext == '.py':
            err = run_script(script, arg)
            if err: # stop processing arguments.
                return
        else:
            script.open(arg)
dataset/ETHPy150Open enthought/mayavi/mayavi/scripts/mayavi2.py/process_cmd_line